GO 336 Mineralogy

Earth Science Department Emporia State University

Susan Ward Aber

http://www.emporia.edu/earthsci/amber/go336/reports.htm

Mineral Economic Value and Use Reports

The students in mineralogy are writing brief reports on the economic value and use of common minerals. Also, they report on any properties of the mineral that can account for this value of these precious natural resources. Their words are shown below.

Silicates
Topaz
Garnet
Chrysotile
Kyanite
Mica
Talc
Beryl
Tourmaline
Quartz
Feldspars
Native Elements
Platinum
Silver
Gold
Copper
Sulfur
Graphite
Diamond
Sulfides
Chalcopyrite
Galena
Pyrite
Sphalerite
Halides
Fluorite
Halite
Oxides/
Hydroxides

Bauxite
Hematite
Magnetite
Carbonate
Calcite
Vanadate
Vanadinite


Silicates


Topaz by Lacey Dreyer

Topaz is one of many minerals that fall in what mineralogist call a nesosilicates. Neososilicate are moderately hard and they usually form short, blocky, somewhat square crystals (Chesterman, 1979). Topaz is an aluminum fluorsilicate, which means that it can have many different colors. Topaz of different colors are found in different parts of the world. For example, pink topaz is found only in Pakistan and Russia. Brown, yellow, orange, sherry and red topaz is found in Brazil and Sri Lanka. There is also a blue topaz, although very little blue is naturally colored, which can be found in Brazil, Sri Lanka, Nigeria, and China (Jewelry Central). The most common color of topaz is yellow with a red tint. The most precious color is the pink topaz because of the agents iron and chromium (Schumann, pg. 102).

Topaz has a hardness of 8 and a specific gravity of 3.4. The crystal system is orthorhombic. It usually has long, prismatic crystals. Topaz looks very much like quartz because of the long and prismatic crystals. The one thing that topaz has the quartz does not is excellent cleavage. The cleavage is the best field mark for topaz and the best way to tell topaz and quartz apart (Chesterman, 1979).

The history of topaz is very interesting because different cultures used it different ways. Most cultures believed that topaz was a gem colored by the rays of the sun which came from the sun good. The Egyptians thought that it would guard them from harm. The Romans associated topaz with Jupiter which was also the sun god. Both cultures believed that it dispels all enchantment and helps to improve eyesight. The ancient Greeks believed that topaz gave the person wearing it strength and that it help in a time of emergency. They said that topaz would change color in the presence of poisoned food or drink (Jewelry Central). In the 18th century, the most famous topaz mine was located in southern Voigtland in Saxony (Schumann, pg.102). The most famous topaz today is a giant specimen set in the Portuguese Crown, the Braganza (Jewelry Central). Today topaz is mainly used for jewelry.

References
Chesterman, Charles. National audubon society field guide to north American rock and minerals. Chanticleer Press, Inc. New York. 1979.

Jewelry Central. JC Store. (1999-2004). Topaz. (WWW). Available: http://www.jewelrycentral.com/Target_Topaz.html. Retrieved 9/9/04.

Schumann, Walter. Gemstones of the world. Revised and Expanded Edition. Sterling Publishing Co., Inc. New York.

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Garnet by Susan Kelley

Garnets are a group of mineral species all having essentially the same isometric crystal structure, but varying in chemical composition and in many of their physical properties. According to Klein (1999), “Garnet compositions can be expressed by the general structural formula A3B2(Si04)3 where the A site houses Ca, Mg, Fe2+ or Mn2+ and the B site incorporates Al, Fe3+, and Cr3+”(p. 452). Six species of common garnets are divided into two series. The series containing aluminum is called Pyralspite as an acronym for the garnets contained in that group: Pyrope, Almandine, and Spessartine. The other series containing calcium is called Ugrandite as an acronym for the garnets contained in that group: Uvarovite, Grossular, and Andradite. The members of each series freely intermingle with each other. However, between the two series of garnets, it is much rarer for them to intermingle.

Garnets are in the nesosilicate class. They crystallize to form in dodecahedral and trapezohedral crystals with a 4/m Bar3 2/m crystal. Specific gravity is 3.4 – 4.18 and their hardness is 6.5 – 7.5. They have no cleavage and streak colorless to white. Their fracture is conchoidal. Garnets occur in all colors except blue and are transparent to opaque. According to the Mineralminers Website “garnet is allochromatic, meaning that most of the color variations in different garnets are due to their highly variable trace element impurities rather than to their bulk composition elements. The color we see in garnets is produced when light is selectively absorbed by ions” (Gem and Mineral Miners, Inc. 2003).

Garnet is the birthstone for the month of January and is the symbolic gemstone for the 18th wedding anniversary. The name garnet is from the Latin word granatus, which originated when garnet grains in rock were compared to the dark red seeds of the pomegranate fruit.

Garnets form in a variety of geologic settings, depending on the garnet species. Some garnets are of igneous origin, but most of them are products of metamorphism. “ The garnet species with red or purple varieties, including pyrope, almandine and a variety intermediate between these two called rhodolite, are considered gemstones”(Chesterman, 1979, p. 585). Garnets can be faceted, and those of deep color are fashioned as cabochons, and are called carbuncles. “In the gem trade, when the term “Garnet” is used, it refers to a garnet of dark red color, and usually to Pyrope or Almandine” (Friedman, 2003). The harder garnets are used as an abrasive, from which garnet paper is made.

References

Klein, C. (1999). The 21st edition of the manual of mineral science (after James D. Dana, Revised 20th Ed.). NY: John Wiley & Sons.

Gem and Mineral Miners, Inc (2003). Garnet Factsheet and Information. Retrieved September 14, 2004 from the World Wide Web http://www.mineralminers.com/html/garminfo.htm

Chesterman, C. W.(1979). The Audubon society field guide to north American rocks and minerals. NY: Alfred A. Knopf.

Friedman, Hershel (2003). The Garnet mineral group. Retrieved September 14, 2004 from the World Wide Web http://www.minerals.net/mineral/silicate/neso/garnet/garnet.htm .

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Chrysotile by Jonathan Howard

Chrysotile comes from the Greek words for golden fiber. While not always golden, chrysotile is definitely fibrous. It is the asbestiform variety of the serpentine group, with a chemical formula of Mg6Si4O10(OH)8. It is monoclinic and has hardness between 2.5 and 5. Chrysotile has a specific gravity of 2.5-2.6, no cleavage and uneven fracture. A greasy luster characterizes this translucent mineral with a white streak. Its color can be white, gray, green, yellow, or brown. Chrysotile yields water when heated (Pellant 158). It is a very common mineral, having been found on every continent except Antarctica. In 1999, the most common location for chrysotile mining was Russia, which produced 36.8 percent of the world’s chrysotile (Chrysotile).

Chrysotile has been used for more than 2000 years. Because it is strong, flexible, and resistant to chemicals, heat, and rotting, it has served many purposes. At first, it was used for cremation cloths, oil lamp wicks, and other textiles (Chrysotile). One of its main uses in the past century was as asbestos insulation, but this has stopped due to health risks associated with asbestiform minerals. Two other asbestiform minerals, amosite and crocidolite were also used, but the majority of asbestos today is chrysotile. Current uses include chrysotile-cement, which is used in building materials because of its durability and low cost. Many friction materials, such as brakes, use chrysotile because of its resistance to heat. Other uses for chrysotile include roof sealants, textiles, plastics, rubbers, door seals for furnaces, high temperature caulking, paper, components for the military and the nuclear industry (Chrysotile).

Works Cited

Chrysotile Institute, The. “Chrysotile.com – Safe and Responsible use of chrysotile – The Chrysotile Institute.” Modified 7 August 2004. Accessed 15 October 2004. http://www.chrysotile.com.

Pellant, Chris. Rocks and Minerals. New York: Doring Kindersley, 2002.

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Kyanite by Susan Kelley

Kyanite is a member of the sillimanite group of minerals. This group also includes andalusite and sillimanite – all of which are naturally occurring polymorphs of Al2SiO5. These minerals are also commonly referred to as the 1:1 alumino-silicates (Kyanite, 2001). The word Kyanite is derived from the Greek word kyanos meaning blue.

Kyanite is usually blue, but can also be white, gray, or green. It is transparent to translucent with a vitreous luster. It has perfect cleavage and a fibrous, splintery fracture. A unique characteristic of kyanite is a wide variation of hardness in the same crystal. The hardness is 4.5 parallel to the long axis of the crystal and 6.5, perpendicular to the long axis. Specific gravity is 3.58+ with a white streak. The crystal system is triclinic, bar 1, with long, flat prisms.

Kyanite is typically the result of regional metamorphism of pelitic rocks and is associated with corundum, garnet, and staurolite. It occurs in kimberlite pipes and in some eclogites. Both of these rock types reflect high to very high pressures of origin (Klein, 2001 p. 457). Notable occurrences include Brazil, Russia, Switzerland, India, Kenya, and the USA. The Kyanite Mining Corporation website offers information about their facilities. The corporation claims to have the most modern processing facility in the world, located in Dillwyn, VA. They have two facilities where they can process over one million tons of kyanite ore per year. A state-of-the-art quality control and lab facility are also located at the plant (Kyanite, 2001).

Kyanite has many important and unique properties that make it a valuable raw material in refractory and ceramic products. Kyanite contains 60% alumina – which means that is a relative cheap source of refractoriness. It undergoes a large and irreversible expansion at 1325 degrees C. This expansion is used by many refractory and ceramic manufacturers to reduce shrinkage during initial firing. The Kyanite Mining Corporation website also offers the following industrial uses of kyanite:

A local manufacturing plant, Thermal Ceramics has experimented using kyanite in the manufacturing of its product. In an interview with Scott Curtis, production manager at Thermal Ceramics, I learned that the company makes insulation by starting with calcined alumina powder from bauxite. Silica sand is added and then the mixture is melted in an electric furnace and air is blown through it. The end product comes out looking like cotton candy. Several years ago they kyanite was added to the mixture. Powdered kyanite was shook into the fiber after it was blown and then reheated. It was hoped kyanite would expand the fiber and make the insulation denser; however, the experiment was not a success because the kyanite expanded into the space between the fibers and was deemed unsuitable in their product (Curtis 2004).

Kyanite has another use as a gemstone. Transparent kyanite crystals may be fashioned into gemstones or used in a natural state. Kyanite is as a gem is rare though and difficult to cut because of the variable hardness and cleavage.

References

Kyanite Mining Corporation (2001). Retrieved September 09, 2004 from the World Wide Web http://www.kyanite.com.

Klein, C. (1999). The 21st edition of the manual of mineral science (after James D. Dana, revised 20th Ed.). NY: John Wiley & Sons.

Curtis, Scott (September 09, 2004) telephone interview.

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The Wonderful World of Mica by Dustin Ross

When I here the word mica it simply makes me think of a thin mineral. After doing this assignment I see I really had no idea what mica was really about. Like myself, most people hear the term mica and simply consider it a mineral in itself. This is not true of course. It is actually a group of phyllosilicate minerals that make up the mica group. “The Mica Group is actually a rather large group of minerals with over 30 members” (Amethyst galleries Inc., 2002). Such minerals in the mica group are muscovite, biotite, and lepidolite. Other micas that are not commonly found would be glauconites, paragonite, and phlogopite.

“The mica minerals are sheet silicates with a three-layer sheet structure and with either K+ or Ca++ and Na++ between the layers.” (Chesterman & Lowe, 1995) Mica minerals have a very thin flake-like structure. Because of this the minerals are very flexible and brittle. The identification of mica is ordinarily not that much of a problem. The perfect cleavage and the shape of the crystals usually is a dead give away. It also has an unmistakable elastic snap in the cleavage flakes. Although the minerals are thin, they are surprising resistant to high temperatures and pressures. The structure of the minerals basically is set up the same way that a building would be constructed; one layer at a time. Aluminum, along with alkalizes, magnesium, and ferrous iron, are what give the micas their well defined makeup.

Micas can be broken down into three major divisions to help in the classification process. The True micas are the first category. These micas hold the majority of the singularly charged ions like in potassium and sodium. Next, are the Brittle micas. These are micas that contain the majority double charged ions, like calcium or barium. Hydromicas or Interlayered-deficient micas is the third division. This is when mica has less or fewer ions than the other micas. All mica minerals fall into one of these three categories.

Micas are found pretty much all over the world so you can see why they are so widely used. In the U.S. alone there was over 97,000 tons of flake and scrap mica production in 2003. (Hadrick, 2004) Out of that tonnage the state of North Carolina produced about 40% of that mica. The states of South Dakota, South Carolina, Georgia, and New Mexico rounded up the remainder of the mica that was mined.

Mica has many uses in our world as we know it today. It can be found in the making of lamp shades to insulator wrapping for wires. Here are few more uses of mica in our society today. It is used to make speaker diaphragms, snow flakes, heat shields, paper, and wave plates. Most paint today can be contributed to mica. Mica is now even being studied for its uses with nuclear activities. Mica is found in rubber products, oil well drilling additives, and in roofing products. When nuclear reactors leak they release radioactive isotopes cesium-137 into the air. “Two researchers have now discovered a form of mineral mica that acts as a highly selective sieve for capturing cesium ions.” (Science News, 2003) Furthermore, mica might help us to be able to safely clean up radioactive spills with out doing any harm to us.

References

(2002). The Mica Group of Minerals. [WWW]. Available: at Amethyst Galleries Inc. http://mineral.galleries.com/minerals/silicate/micas.htm. Retrieved 9/8/2004.

(2003). A sieve for selecting cesium. Science News, 133(13), 203-204.

Chesterman, C.W. & Lowe, K.E. (1995). National audubon society field guide to north American rocks and minerals. New York: Alfred A. Knopf.

Hadrick, J.B. Mica Statistics and Information. [WWW]. Available: http://minerals.usgs.gov/minerals/pubs/commodity/mica. Retrieved: 9/8/2004.

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The Wonderful World of Talc by Dustin Ross

The name talc comes from the Arabic word “talq” which means mica. It is a hydrous magnesium silicate mineral consisting of about 63.5% SiO2, 31.7% MgO and 5% water. (http://geology.csupomona.edu). Talc has some very unique characteristics. The color of talc may be white, gray, green or even silver. However, green and white are the most common. It has a dull luster and a hardness of one on the Moho scale. The crystal habits of talc are very mischievous. It never forms in large crystals and is found in compact or lamellar masses. (http://mineral.galleries.com) The specific gravity of talc is 2.7-2.8 while the leaves a specific white streak mark. Cleavage is perfect in are direction while the fracture of talc is uneven. (Chesterman & Lowe, 1979).

Some of the first reported talc production was from the eastern Mojave desert in 1910. (www.geology.csupomada.edu). California was a significant talc producer from about 1910 to 1978. The state alone accounted for about 10-20% of the United State’s total talc production. When Congress set up the National Park Conservation laws it closed off the talc mines in Death Valley. However, talc can be found in many areas throughout the United States including New York, Connecticut, Vermont and Montana, who now produce the most talc in the U.S. (Chesterman & Lowe, 1979). Today, France holds the world’s largest talc mine while other countries such as the United Kingdom, Mexico, Spain and Austria mine most of the remaining talc in the world (Mining Industry, 2003).

Talc is one of the worlds most versatile minerals. Industrial materials base a lot of their product with talc. Furthermore, because talc is heat, electrical and acid resistant it makes use as a good lab countertop (Mineral Galleries). Paints, plastics, rubbers and ceramic material can also be made with talc.

Talc also makes its way into a lot of consumer products that we use everyday. Talc is used widely in both cosmetics and soaps because it is both odorless as well as impurity free (www.golcha.com). Talc gives cosmetics the stability they need as well as helps the products adhere to the skin and become water resistant (www.golcha.com). Talc is used as filler in many soaps acting as a binding agent. It is even used in many washing detergents, pharmaceuticals, and animal feed. Talc is also used in shoe polish, floor wax, printer ink, and bleaching agents. (www.golcha.com).

Over the past few years talc has derived much controversy over its use. This is due to the studies of talc related pneumonia from talcum powder inhalation (Medical Update, 2002). Many studies have been conducted over talc inhalation in talc mines. Furthermore, there has been significant evidence contributing lung disease to talcum powder. This evidence has urged the United States government to put out warnings about the use of talc and has also lead to a decreased amount of talc being used in the powder form.

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Beryl by Lacey Dreyer

Walter Schumann refers to beryl as a species in his book on gemstones. What does that mean? Well there are many varieties and forms of beryl. First is the general description of beryl before we talk about the different species. Beryl can be several different colors. The colors are cause by impurities in the mineral. The hardness of beryl can range from 7.5 – 8 on the Mohs hardness scale. The crystal system is hexagonal, usually six – sided prisms that are striated lengthwise (Chesterman, 1979). The environment that it is form in is metamorphic rocks and pegmatite. Beryl is a mineral of very old, deep, buried rocks. So it is almost always associated with a pegmatite mineral. It can also form in very high-temperature veins and pockets of beryllium-bearing gases or very hot solutions (Minerals – n – More). Beryl can be found in several places all over the world such as New England, North Carolina, Colorado, California and Nevada.

There are three types of beryl that are common in everyday life. First is emerald, which is the green color of beryl. Emerald is probability the most precious stone in the beryl group. The color green is caused by the agent chrome and is often irregular in color, meaning that the shade of green is not always the same throughout the stone. All emeralds are brittle and can break easily and they are resistant to all household chemicals. Mining of emeralds most always come from a host rock where they have grown into veins or in cavities of the host rock (Schumann, p. 90). Well known emeralds of several hundred carats can be found in the British Museum of Natural History in London, the American Museum of Natural History in New York, and the Treasuries of Russia, Iran, and Istanbul, Turkey.

The second in the beryl species is aquamarine, which is Latin for water of the sea. The color of aquamarine is a very light blue like the color of the sea. The agent that is responsible for the color is iron. Aquamarine is also very brittle, so take care not to hit is against anything. In 1910, the largest gemstone quality of aquamarine was found in Marambaya, Minas Gerais, Brazil. It weighted 243 pounds, was 18 inches long and was 15.5 inches in diameter. When it was cut into smaller stones it’s to carat weight was over 100,000 (Schumann, p. 94).

The third in the beryl species is what is called the precious beryl. Precious beryl means beryl of special colors. Bixbite is a raspberry red color form of beryl and in found in Utah. Golden beryl color varies between yellow colors and is found in Brazil, Madagascar and Nigeria. Goshenite is a colorless beryl and was named after the area where it was found at, Goshen, Massachusetts. Heliodor is a light yellow- green color beryl. This type of beryl is generally rejected as a precious beryl. The precious status is usually associated with golden beryl. Morganite is a pink color of beryl and was named for the American banker and collector J.P. Morgan (Schumann, p. 96).

References

Chesterman, Charles. National audubon society field guide to north American rock and minerals. Chanticleer Press, Inc. New York. 1979.

Minerals – n – More. Minerals A – Z. Beryl. (WWW) Available: http://www.minerals-n-more.com/Info_Beryl_Family.html. Retrieved: 9-22-04.

Schumann, Walter. Gemstones of the world. Revised and Expanded Edition. Sterling Publishing Co., Inc. New York.

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Tourmaline by Jonathan Howard

Tourmaline is not one specific element, but rather a group of several similar elements. All have very similar chemical formulas, but a change in one or two of the elements present can cause large changes in appearance. The name comes from the Singhalese word for brown, as the first specimens found were brown in color. Tourmaline has a hardness of 7 to 7.5, a colorless streak, a hexagonal crystal system, and does not cleave very well. It has been found in many locations throughout the world, including Brazil, Mozambique, Nepal, Norway, and Australia (Boegel 221-222).

The basic formula for tourmaline is AX3Y6(BO3)3 Si6O18(O, OH, F)4 (Galleries). A, X, and Y change, producing different varieties of tourmaline. Black schorl, the most common variety, contains sodium, iron, and aluminum. The name comes from the slang term German miners used for the mineral. Sodium, lithium, and aluminum tourmaline is called elbaite, and can be pink, blue, green, red, or colorless. Sodium, magnesium, and aluminum create dravite, a brown variety. Because of how little of a change is required to produce different colors, some crystals can contain several different colors. Watermelon tourmaline is produced when a green crystal forms around a red crystal, which resembles a watermelon in cross-section.

In the 1700s, the Dutch collected tourmaline from Sri Lanka, for use as ash attractors, because tourmaline, when warmed, has a tendency to attract dust and ashes to itself (Boegel 221). When squeezed, it produces an electrical charge, which has been used to measure pressure. Aside from these uses, tourmaline is mainly used as a gemstone in jewelry, and has large significance in crystal healing.

Works Cited Amethyst Galleries, Inc. Amethyst Galleries- TOURMALINE GROUP. Last update 2002. Retrieved 24 September 2004.

Boegel, Hellmuth. The Studio Handbook of Minerals. 2nd edition, New York: Viking Press, 1972. Originally Zurich: Droemersche Verlagsanstalt, 1968.

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Quartz by Jonathan Howard

Quartz, silicon dioxide, is one of the most common minerals on Earth. It has been found in numerous places on Earth, with more famous deposits in Brazil, France, and Arkansas (Locations). Color varies greatly, but the most common colors are white quartz, colorless/clear quartz, and milky quartz. Less common are pink, or rose, purple, or amethyst, and yellow, or citrine. It is a relatively hard mineral, with a hardness of seven, a white streak, and a conchoidal fracture. It insoluble, “…unless placed in hydrofluoric acid” (Pellant 86).

Quartz has been used for decorative purposes for many years. Pliny described quartz crystals in detail, and noticed that it was used in carvings in ancient Rome. In the 1500s and 1600s, decorative vases were carved from quartz. Amethysts are used in rings, and rose quartz has been used in necklaces.

Quartz has many more industrial uses. Sand, very small pieces of quartz, is a major component of glass. The ingredients are heated until melted, and shaped before they are able to reform into crystals. It is used as an abrasive in grinding and sandblasting, and cutting softer stones. Quartz also has many electronic uses, such as in radios, pressure gauges, computers, and fiber optic cables. A source of the ingredients for synthetic quartz is sometimes real quartz, usually reshaped to form more perfect crystals (Arkansas).

Works Cited

Arkansas Geological Commission. Quartz (Industrial). http://www.state.ar.us/agc/quartz.htm. Accessed 10 September 2004.

JewelrySupplier.com. Locations of Quartz mines and sources and descriptions of samples from each. http://www.jewelrysupplier.com/2_quartz/Quartz_geography.htm. Accessed 11 October 2004.

Pellant, Chris. Rocks and Minerals. London: Dorling Kindersley, 2002.

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Native Elements


Platinum by Lacey Dreyer

Platinum is considered one of the most precious metals. Other precious metals include gold and silver. Platinum is part of the Platinum Group Metals or PGM. The PGM include platinum, palladium, rhodium, ruthenium, iridium and osmium. Out of this ground of PGM, platinum and palladium are the most important (UNCTAD, 2004).

Platinum is usually a white, grey or steel color and is shinny. It has a hardness of 4-4.5 on Mohs Scale of Hardness. The crystal system is isometric, typically found in distorted cubes. Platinum is found in the following shapes: grains, lumps or nuggets. Platinum is not found by itself, it is more often than not found in placer deposits (Chesterman, 1979).

The history of platinum dates back as far as 700 B.C. where the ancient people noticed the little grey pebbles. The pebbles were known as platina del Pinto, which means granules of silver material. The pebbles came from the Pinto River in the San Juan River Valley in Colombia (Gold and Silver Mines, 2004).

Mining of platinum is a very long and complex process. To mine platinum requires a complex aqueous chemical process in order to isolate and identify that it is platinum. These techniques were not available in the ancient times, but needed techniques came about in the 19th century. That is why the platinum group has lagged behind silver and gold by thousands of years for use (Gold and Silver Mines, 2004). The major mining districts for platinum are in South Africa and Canada.

Platinum has many different applications and uses. First is auto catalyst, which is the cat converter in the car. It helps control pollution out of the car. Platinum can also be used as a catalyst for chemical, fuel cells and petroleum. Platinum is also found in electronics such as computers. Platinum can also be an investment such as coins and bars. Other applications and uses would include dental, glass, jewelry, spark plugs and pollution control (UNCTAD, 2004).

References

Chesterman, Charles. National audubon society field guide to north American rock and minerals. Chanticleer Press, Inc. New York. 1979.

Gold and Silver Mines. More about Platinum (WWW). Available: http://www.goldandsilvermines.com/platinum.htm. Retrieved 9/28/04.

UNCTAD. Market Information in the Commodities Area. Info Comm. Characteristics of Platinum (WWW). Available: http://r0.unctad.org/infocomm/anglais/platinum/characteristics.htm. Retrieved 9/28/04.

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Silver by Susan Kelley

Silver is in the native element class and the gold group. Silver was known to ancient civilizations and has been mined for eons. Its name comes from the Old English word seolor.

It has a hardness of 2.5 - 3 and a high specific gravity of 10.1 - 10.5. No cleavage is present and its color and streak are silver-white. It is opaque with a metallic luster and hackly fracture. Silver's crystal system is isometric with 4/m bar 3 2/m. Cubic or octahedral crystals occur, but are very rare. It usually occurs dendritic, wiry, massive, as grains and scales, and as groups of tiny crystals. Silver is not radioactive, but is ductile and malleable. Silver is a very resistant mineral. It does not dissolve in most solutions, and won't react to oxygen or water. Its weak point is its reaction to sulfur and sulfides, which cause it to tarnish black, brown to gray, and dark yellow. It is the best conductor of electricity.

Most silver is extracted from silver ores, but considerable amounts are mined from native silver. It is frequently mixed with gold; and sometimes with mercury, arsenic, and antimony. Silver occurs in primary hydrothermal veins, secondary enrichment, and as alluvial nuggets. According to Chesterman (1995), notable collecting localities are mines on the Keweenaw Peninsula, Michigan; Bisbee, Cochise County, Arizona; and Creede County, Colorado (p. 347-348). Sheets and masses of silver, with many of notable size that is inches across, have been collected from the veins at Cobalt, Ontario, while silver in a wire habit, at Batopilas, Chihuahua, Mexico (p 347-348). Friedman says “some of the finest silver has come from Kongsberg, Norway, where beautiful crystals and wiry masses occur with calcite and silver sulfides” (Friedman 2000).

Silver is used as jewelry, ornaments, circuits, electrical apparatuses and coins. It is also used for medicinal purposes, particularly in dentistry, for bactericides, and for antiseptics. In the past, it had been used as the reflective surface for mirrors. Silver is also used in the photography industry, which takes advantage of silver's reactivity to light. With the invention of digital cameras, this use has decreased.

Sterling silver is .925 fine with the rest of the mixture usually copper. Coin silver is 90% silver and 10% copper. The silver market offers investors a variety of products. Pre-1965 U.S. 90% coins serve both as an investment medium and are permanent wealth as opposed to paper wealth. Weights of silver coins follow:

* Silver dollars contain 0.77344 Troy oz. silver content
* Half dollars contain 0.36169 Troy oz silver content
* Quarters contain 0.18084 Troy oz silver content
* Dimes contain 0.0723 Troy oz silver content

You can calculate the value of each coin by multiplying the silver content by the current spot price of silver, which is $6.68 (Bullion, 1999 - 2004).

References

Chesterman, C.W. (1995). The Audubon Society field guide to North American rocks and minerals. NY: Alfred A. Knopf.

Friedman, Hershel (1997 - 2000). Silver. Retrieved September 27, 2004 from the World Wide Web http://www.minerals.net/mineral/elements/silver/silver.htm.

Bullion Direct (1999-2004). Market summary. Retrieved September 29,2004 from the World Wide Web http://www.bulliondirect.com.

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Gold by Jonathan Howard

Gold is one of the native element minerals, along with silver, platinum, arsenic, sulfur, and others. The chemical formula is simply Au, but it can be difficult to find pure and is often found combined with silver, copper, or platinum. It is in the cubic crystal system, with crystals forming as octahedrons or cubes, but good examples of gold crystals are rare. It usually occurs as nuggets, grains, or flakes. Gold has a bright yellow streak, a hardness of 2.5 to 3, a specific gravity of 19.3, poor to no cleavage, and is mostly insoluble in acid. Aqua regia, a 3:1 mixture of hydrochloric acid and nitric acid, is one of few substances gold is soluble in; gold is usually tested with aqua regia. Because of gold’s color, it can be confused with pyrite or chalcopyrite, but a hardness or streak test will show the difference. Usually found in veins in quartz or sulfides, it can also be found in riverbeds by panning. It has been found in the United States, famously in California and Alaska, in Australia, South Africa, Romania, Russia, and Germany (Boegel 67-68).

Gold has been well known, and enthusiastically hunted, throughout history. Ancient Egypt believed gold was the flesh of the gods. The story of Midas also shows an early view of gold as highly valued and worthy of kings. The European explorations of North and South America in the 1500s and 1600s were in some part inspired by tales of El Dorado, a city where every building and street was made of gold. Many countries have used or currently use gold as their currency’s standard.

Today, gold is a highly valuable mineral, at the time of writing worth $419.60 (World Gold Council). Its high conductivity, reflectivity, ductility, malleability, and resistance to corrosion make it highly useful in industry. Gold was used as a radiation shield during the Apollo missions, and as a heat shield on space shuttles. It is often used in electronics to plate contacts, to help dissipate heat, and because of its resistance to corrosion can be used in a large variety of environments. Its malleability and resistance to corrosion make it good to use in dental work, though because of its low hardness it is usually used combined with silver, platinum, or copper. Gold is highly valued in decoration, used for plating in jewelry, construction, and many other products.

Works Cited

Boegel, Hellmuth. The Studio Handbook of Minerals. Second Edition. London: Thames and Hudson, 1971.

World Gold Council. World Gold Council The Global Advocate for Gold. Retrieved 01 October 2004. http://www.gold.org/index.html

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Copper is Everywhere by Dustin Ross

Copper is a copper-colored metallic ore which leaves a reddish copper color streak (Schumann, 1992). It has a hardness on Mohs' hardness scale of 2.5-3 and has a specific gravity of 8.93 (http://www.minerals.net). It is a biostatic mineral with a melting point of 1,981 degrees Fahrenheit (http://www.azcu.org). Copper's fracture is jagged and has no cleavage. It is a very versatile mineral because it can be molded into various shapes, cut into slices and even stretched into wire (http://mineral.galleries.com).

Copper was first discovered in the Middle East thousands of year ago. It was first intended to be used in the making of fine jewelry (http://www.azcu.org). It was later named after the Greek Kyprios, the island of Cyprus, where it was first mined (Chesterman & Lowe, 1995). Cooper soon evolved to be used as not only jewelry but also as cooking dishes, mirrors and even as statues (http://www.azcu.org). In fact, one of the most well-known statues in the United States, the Statue of Liberty (or “Liberty Enlightening the World” as it is originally titled) contains 179,200 pounds of copper (http://www.endex.com). Today, copper still makes itself valuable by being used by a wide variety of products.

Native copper is the most natural form of copper, which today is very rare. Because other copper minerals are much more economic to use, this native copper has not made its name as being a practical ore. Native copper can be found all over the world in places like Russia, Australia, and Germany, as well as in the United States in states such as Arizona and Michigan (http://mineral.galleries.com). In earlier times it was used by early civilizations to make weapons for hunting and self-defense; however, it was later replaced by iron because of iron's durability. Today, there are over 400 alloys in which copper is the basic metal. For example, copper can be alloyed with tin to become bronze or combined with zinc to become brass (http://www.azcu.org); both of which are widely used in present times.

Silver holds the best record for the ability to conduct electricity; however, copper comes in second and is even cheaper and more prevalent than silver which makes it widely used for conducting electricity (http://www.azcu.org). Subsequently, copper is used in four major markets besides electrical and electronic products: construction, transportation equipment, industrial machinery and equipment, and general consumer products (http://www.azcu.org).

Construction uses up 2,950,000,000 pounds of copper each year (or forty percent of copper used in the United States). Its main purposes in this context are for plumbing and electrical wiring. In fact, the average American home will use an average of 400 pounds of copper for its construction. In addition, an individual today will use about 1,750 pounds of copper in his or her lifetime in products, transportation, electricity and housing.

Transportation accounts for thirteen percent of copper used in a year. It is used in cars, trains, and even submarines (http://www.azcu.org.). Copper is even used to make jet planes and Space Shuttles (http://www.azcu.org).

Industrial machinery and equipment account for twelve percent of total copper use. Copper is used to make almost everything that we enjoy as humans such as clothes and food (http://www.azcu.org).

General consumer products hold the last market for copper with over 745,000,000 pounds, or ten percent of total copper use (http://www.azcu.org). We really do take for granted all that copper does in this category. Copper is in many items we use everyday such as: pennies, alarm clocks, radios, doorknobs, coffeemakers, car keys, zippers, forks and spoons, wedding bands and even eyeglasses (http://www.asarco.com). Copper is everywhere!

References

Arizona Mining Association. Copper as Commodity: Past and Present, The Uses of Copper. [WWW] Available: http://www.minerals.net. Retrieved on 9/27/2004.

Copper-A Fact Sheet. [WWW] Available: http://www.azcu.org. Retrieved on 9/27/2004.

Chesterman, C.W. & Lowe, K.E. (1995). National Audubon society field guide to North American rocks and minerals. New York: Alfred A. Knopf.

Liberty Facts. [WWW] Available: http://www.endex.com. Retrieved: 10/1/2004.

Life with Copper. [WWW]. Available: http://www.asarco.com. Retrieved on 9/27/2004.

Native Copper. [WWW] Available: http://mineral.gallaries.com. Retrieved on 9/27/2004.

Schumann, W. (1992). Minerals of the world. New York: Sterling Publishing Company.

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Sulfur: The Stinky Stuff by Dustin Ross

Webster's dictionary defines sulfur as, “a yellowish, nonmetallic element occurring naturally in both combined and free form, used in making matches, gunpowder and medicines” (Molino & Suplicki, 1996). The mineral sulfur is sometimes given a bad reputation due to the rotten egg smell odor it produces. Nevertheless, sulfur plays a big role in our world today.

Sulfur was first described by the ancients in the Bible's book of Genesis as brimstone (www.speclab.com). It is a mineral that possesses many interesting physical characteristics. It has a hardness of only two on the Mohs hardness scale. This makes the mineral very light and loosely packed. Therefore, sulfur has a conchoidal fracture; as well as a poor cleavage in only two directions. Sulfur is yellow in color and leaves a yellowish streak on the steak plate. However, sulfur can also show a reddish or greenish yellow color with impurities (http://.mineral.galleries.com). The simple yellowish color is what gives sulfur its unique ability to stand out among other minerals. The unmistakable deep yellowish color is not matched by any other mineral. The specific gravity of sulfur is only 2.0-2.1. This is considered well below average for specific gravity (Chesterman & Lowe, 1995). As for the shape of sulfur, there is not much to it. The crystal habits include mostly massive or powdery forms while the crystal system is orthorhombic having a 2/m 2/m 2/m crystal class. Sulfur possesses very poor heat conductivity which makes it very brittle when heat is applied to it. It is usually accompanied with other minerals like calcite, gypsum, halite and celestite (Schumann, 1992).

As a kid I remember visiting my aunt in Houston and driving down the road to Galveston, Texas for some sight seeing. I strictly remember driving by the ship yards and seeing a very disturbing odor. Come to find out, the odor was coming from outside the car and not in the car. We happened to be driving downwind of a sulfur stock pile yard. My aunt just told me that it was what sulfur smells like. In doing the paper, I found that she was right in one way but wrong in another. Yes, the smell was coming from the sulfur piles but sulfur alone does not produce the rotten egg smell. The sulfur smelled because it had a reaction to water, that is the odor occurs when sulfur mixes with water. This mix will produce a small amount of hydrogen sulfide gas, which we recognize as the rotten egg smell (www.speclab.com). Thus, being close to the Gulf of Mexico the sulfur piles were susceptible to rain water and humid air, and often smelled of rotten eggs.

You do not have to go far from the United States to find sulfur. It is most commonly found in salt domes along the Gulf coast of the U.S. This is why the United State's main stock piles of sulfur are along the Gulf coast. Sulfur is found in Michigan, Ohio, Texas, and Louisiana. Overseas sulfur is found in countries including Italy, Japan, Romania, Mexico, and the Commonwealth of Independent States. It is usually mined through the Frasch process (www.speclab.com), where hot water is pushed in the ground to melt the sulfur and then a liquid sludge is brought up to the surface. However, sulfur can also be mined through digging, screening, and shoveling.

Sulfur has many uses in our society today. The number one thing sulfur does for us is that it helps us start fires. A majority of all match stick heads contain sulfur. It is also found in many plastics, enamels, rubbers, and in fertilizers. Sulfur is one of the main components that make up gun powder. If you pick up some acne ointments and face cleaners, you can bet they probably have sulfur in them. It is placed in cattle feed and in many insecticides (www.speclab.com). Because sulfur has low electrical conductivity, it is used for insulating equipment. Sulfur is one of the primary elements that are used in constructing the incendiary-Bombs (also known as NAPOM bombs) for the U.S. Throughout time sulfur has demonstrated its usefulness in a plethora of ways. As our scientific technology vastly improves in the future, we can be assured that sulfur will always be a mineral in demand.

References

Chemical Fact Sheet-Sulfur. Retrieved from www.speclab.com on October 12, 2004.

Chesterman, C.W. & Lowe, K.E. (1995). National Audubon Society Field Guide to North American Rocks and Minerals. New York: Alfred A. Knopf.

Molino, G. & Suplicki, C. (Eds.). (1996). Webster's Dictionary and Thesaurus. Native Sulfur. Retrieved from http://mineral.galleries.com on October 12, 2004.

Schumann, W. (1992). Minerals of the World. New York: Sterling Publishing Company.

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Graphite by Susan Kelley

Graphite is in the native element class and subclass non-metallics. It is a polymorph of the element carbon. Diamond is the other polymorph. The two share the same chemistry, carbon, but have very different structures and very different properties. According to the mineral galleries website:

· Diamond is the hardest mineral known to man, Graphite is one of the softest.

· Diamond is an excellent electrical insulator, Graphite is a good conductor of electricity.

· Diamond is the ultimate abrasive, Graphite is a very good lubricant.

· Diamond is usually transparent, Graphite is opaque.

· Diamond crystallizes in the isometric crystal system and graphite crystallizes in the hexagonal crystal system (AmethystGalleries, 1996).

All of the differences between diamond and graphite are the result of the difference in their respective structures. Graphite has a sheet like structure where the atoms all lie in a plane and are only weakly bonded to the graphite sheets above and below. Diamond has a framework structure where the carbon atoms are bonded to other carbon atoms in three dimensions as opposed to two in graphite. Graphite has perfect , one directional cleavage.

Graphite is dark gray to black and streaks black. It has a hardness of 1 – 2 and a specific gravity of 1.9 – 2.3. Graphite will smudge the hands and feel greasy. It has a brittle tenacity, but thin flakes can be slightly elastic. Its luster is greasy to sub-metallic. Flaky to sectile is its fracture. The minerals.net web site says other names for graphite are black lead, plumbago, pencil ore, and graffito (Friedman 2000).

Graphite results from the metamorphism of carbonaceous material in sedimentary rocks and is found with quartz and muscovite in schists of regional metamorphic rocks and in marble. Some graphite is found in igneous rocks and also as nodules inside of iron meteorites. Graphite is rather common, but fine crystals are rare. Chesterman notes that “fine crystals have been found in the marbles at the Sterling Hill Mine at Ogdensburg, Sussex Co., New Jersey; in schists in Clay Co., Alabama; and in massive veins near Ticonderoga, Essex Co., New York” (Chesterman, p. 356).

The name is derived from the Greek graphein, to write, in allusion to its use as a crayon. The lead in pencils is not lead, but graphite mixed with clay. Much of the mined graphite is used in pencils. Its main function, however, is as a lubricant. Other uses are for brushes in electrical motors, friction materials, and battery and fuel cells.

References

Amethyst Galleries, Inc. (1996) Graphite (carbon) Retrieved October 16, 2004 from the World Wide Web http://mineral.galleries.com/minerals/elements/graphite/graphite.htm. Friedman, H. (1997 - 2000) The mineral graphite. Retrieved October 16, 2004 from the World Wide Web http:///www.minerals.net/mineral/elements/graphite/graphite.htm. Chesterman, C.W. (1995). The Audubon Society field guide to North American rocks and minerals. NY: Alfred A. Knopf.

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Diamonds: Not Just Girls Best Friend by Dustin Ross

Because of it's natural physical characteristics and beauty, the diamond has been labeled a symbol of love, beauty and eternity. Some consider it the ultimate gemstone, possessing very few weaknesses and much strength! It is one of the world's most precious materials. The term diamond actually comes from the Latin word adamas. This term is also used in the Greek language. Adamas, in both languages, means hard invincible (Chesterman & Lowe, 1995). This is why the diamond has been one of the world's most valued natural minerals for what seems an eternity!

The diamond has many impressive physical characteristics. However, one physical property really stands out, this mineral's hardness, of course. Diamond possesses a perfect ten on the Mohs Hardness Scale. This is the top seat of the hardness scale (www.mineral.galleries.com). In fact, very few people realize that the diamond is really many, many times harder than the next hardest mineral, corundum or the ruby and sapphire, which is 9 on the scale (www.mineral.galleries.com). The color of the diamond is very variable when found in nature. It is usually a pale yellow, brown, or gray, but it can be found in blue, reddish pink, green, black, or simply colorless. Its rough luster is waxy, but when polished it takes on the highest luster of a transparent mineral, adamantine. Its transparency is transparent to translucent, but also opaque. The cleavage is perfect in four directions, although it can fracture conchoidally (Chesterman & Lowe, 1995). The thermal conductivity of the diamond is five times better than that of silver. Diamonds are the second best elements that conduct heat and electricity (www.state.ar.us). Specific gravity is at 3.5 and the melting point is high, at about 3,820 degrees Kelvin. Diamonds have a very high refraction and a low reactivity to chemicals like acids (Schumann, 1992).

The diamond is a mineral that is really composed of one simple element, carbon. The carbon elements are arranged in a polymorph form. Graphite is another mineral that is composed primarily of carbon. However, graphite's carbon atoms are not as tightly packed and as well sorted as they are in diamond. That is why graphite is very weak as compared to diamond.

When people think of diamond they mostly think of a sparkling gem that is worth a lot of money. In part they are right. Diamonds are at the top of the list for gems and jewelry. Even more so for individuals with April birthdays, because diamond is the birthstone for April. With its sparkling glow and fire in the light, one can see why it is highly valued in the jewelry industry. However, the gemstone industry is not the leader in diamond consumption. The gemstone industry only accounts for about 20% of total diamond use. The other 80% of diamond use goes to industrial purposes (www.mbendi.co.za). This is due to the fact that a majority of all diamonds found in the world are not of gem quality. Even if the diamonds were to have insufficient size or visible flaws, it would still be priceless to the industrial world.

Being the hardest mineral on Earth, diamond plays a major role in the world's industrial market. Diamonds are abrasives and primary used for shaping and cutting, including diamond cutting knifes, saw blades and sharpeners, which would cut glass, tile, rocks, minerals, and even other diamonds. Sharpening scissors, knives, axes, exacto blades, and fishing knives provide additional uses for diamond (www.eze-lap.com).

Diamonds are only located in a few countries of the world. Australia is the world's leading industrial diamond producer; while Russia, Botswana, and South America are leading gem diamond producers (www.mbendi.co.za). In North America, diamonds are found in Arkansas, Colorado, and Wyoming.

Diamonds are truly one of the world's most magnificent creations of nature. It is one of the only minerals that has a magnificent effect on people, appreciated for both it's gem and industrial uses. I can now see why they say a diamond is truly a best friend!

References

Arkansas Geological Commission. Diamonds(Industrial). Retrieved from http://www.state.ar.us on October 18, 2004.

Chesterman, C.W. & Lowe, K.E. (1995). National Audubon Society Field Guide to North American Rocks and Minerals. New York: Alfred A. Knopf, Inc.

EZE-LAP Diamond Products. Retrieved from http://www.eze-lap.com on October 19, 2004.

The Mineral Diamond. Retrieved from http://mineral.galleries.com on October 18, 2004.

Schumann, W. (1992). Minerals of the World. New York: Sterling Publishing Co., Inc.

World: Diamond Mining-Commodity Properties and Uses. Retrieved from http://www.mbendi.co.za on October 18, 2004.


Sulfides


Chalcopyrite by Lacey Dreyer

Chalcopyrite is a copper iron sulfide, often found with silver and gold. The chemical composition for chalcopyrite is CuFeS2 which puts it with the sulfides, arsenides and tellurides class. The color of chalcopyrite can be any color except white or pale gray. It streaks yellow brown and is metallic to submetallic. The hardness ranges from 3.5 to 4 and the specific gravity is 3.9 through 4.1. Chalcopyrite has perfect cleavage in six directions. It is brittle and can be fluorescent. Chalcopyrite is found in the isometric crystal system with tetrahedral and dodecahedral forms being common (Chesterman, 1979).

Chalcopyrite is also known as peacock ore because of it beautiful coloring. The color is due to tarnishing which will change the colors to brilliant iridescent hues. The word chalcopyrite comes from the Greek word chalkos which means copper and pyrites which means strike fire (Minerals-n-more).

Chalcopyrite is also a major ore of copper. The yield of chalcopyrite out of an ore of copper is very low. It is used for collector specimens and as a decorative stone (Minerals-n-more). It has also been used for healing and energy work. Some people believe that chalcopyrite has healing powers such as protection from illness. It also enhances knowledge and strengthens perception (Harton, 2002). The occurrence of chalcopyrite is widespread. The main sites of large chalcopyrite specimens are found in Pennsylvania (Chester County), Missouri, Kansas, Oklahoma, Arizona, and Utah in the US, as well as Mexico and Quebec, Canada (Chesterman, 1979).

References

Chesterman, Charles. National Audubon society field guide to North American rock and minerals. Chanticleer Press, Inc. New York. 1979.

Harton, Robyn (2002-2004). Crystals and Jewelry. Chalcopyrite. (WWW) Available: http://www.crystalsandjewelry.com/crystalsandstones/chalcopyrite.html. Retrieved 10/14/04.

Minerals-n-More. Minerals A-Z. Chalcopyrite. (WWW) Available: http://www.minerals-n-more.com/Chalcopyrite_Info.html. Retrieved 10/14/04.

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Galena by Lacey Dreyer

Galena is among one of the most popular minerals for anyone to have in their collection. It is among the favorites for high school and college classes as it is easily recognizable (Amethyst Galleries Inc, 1996). The name galena came from the Latin word galena, which means lead ore. The color of galena is a dark gray to silver and has a luster that is metallic. On of the easiest ways to tell if a specimen is galena is by its streak which is dark gray. The hardness of galena is 2.5 on the Moh’s scale of hardness and has perfect cleavage in three directions at 90 degree angle. Galena is in the isometric crystal system and is usually found in cubes (Chesterman, 1979). Other minerals that are also associated with galena are calcite, dolomite, sphalerite and pyrite. Galena can be found all over the United States especially in Oklahoma, Kansas and Missouri. The specimens found in this area are of the cubic and octahedron forms. Other states include Colorado, Idaho and California. Galena can also be found in Germany, Peru, Mexico, Zambia and England.

Galena is also referred to as lead ore because it is a lead sulfide. If someone was to streak it on a white paper it would leave a mark just like a pencil would. Galena is the most significant lead mineral. Most galena deposits have been worked for there lead content (Mineral Information Institute).

Lead is used in many ways and it is found in different things. Lead is used in batteries, gasoline tanks, seals and bearings on a vehicle. It is also used in electrical and electronic applications. Lead is also used to protect human form X-ray and gamma radiation. The biggest use of lead would be in ammunition. During the Civil War the army mad bullets from lead that was derived from a galena mine located in New York (Mineral Information Institute). It is estimated that lead worldwide exceeds 1.5 billion tons. More than one million tons of lead is recovered from recycling.

Reference

Amethyst Galleries Inc. 1996. (WWW) The Mineral Galena. Available: http://mineral.galleries.com/minerals/sulfides/galena/galena.htm. Retrieved 10/21/04.

Chesterman, Charles. National Audubon Society Field Guide to North American Rock and Minerals. Chanticleer Press, Inc. New York. 1979.

Mineral Information Institute. (WWW) Lead. Available: http://www.mii.org/Minerals/photolead.html. Retrieved 10/21/04.

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Pyrite by Susan Kelley

Pyrite is a very common mineral and is found in a wide variety of geologic formations, especially in hydrothermal veins. It is the most widespread and abundant of the sulfide minerals, with a chemistry of FeS2. Pyrite is a polymorph of marcasite, meaning they have the same chemistry. They are separate minerals as they have different structures and therefore different symmetry and crystal shapes. Pyrite is in the isometric crystal system (2/m bar 3), while marcasite is in the orthorhombic crystal system. Pyrite most often occurs as cubes, pyritohedrons, and octahedrons. Crystals are usually striated.

Pyrite has a hardness of 6 – 6.5 and a specific gravity of 4.9 – 5.2. It is brittle, has a conchoidal fracture, and a metallic luster. No cleavage is present and it is opaque. According to the web mineral web site “pyrite is magnetic after heating” (Barthelmy, 2004).

Pyrite is commonly called Fools Gold because of its similarity in color, shape, and habit to gold. They can easily be distinguished by pyrite’s black streak and gold’s yellow streak. Also, gold is softer with a hardness of 2.5 – 3.

Pyrite was polished by the Native Americans and used as mirrors. The word pyrite comes from the Greek, pyrites lithos, stone which strikes fire, in reference to the sparking produced when iron is struck by a piece of pyrite.

The mineral galleries website tells us that although pyrite is common and contains a high percentage of iron, it has never been used as a significant source of iron. Pyrite is not as economical as the iron oxides hematite and magnetite. These ores form larger concentrations of more easily mined material. Pyrite would be a potential source of iron if these ores should become scarce (Amethyst Galleries, Inc., 1996). Pyrite has been mined for its sulfur content. During WWII, sulfur was in demand as a strategic chemical and North American sulfur mines were drying up. “A sulfide deposit near Ducktown, TN. was found to be able to mine pyrite and other sulfides and produce the needed sulfur as well as iron and other metals” (Amethyst Galleries, Inc. 1996).

Excellent collecting localities are numerous in North America. Among the most prominent are the American Mine in Bingham Canyon, Utah; Park City, Utah; Gilman, Leadville and Rico, Colorado; Sparta, Illinois; and French Creek Mine in Chester Co. Pennsylvania (Chesterman, p.374 – 375).

Pyrite is used as an ornamental stone, as well as a popular stone for collectors. It is sometimes used as a gemstone by being faceted and polished for use as a side jewel in a ring, bracelet, or necklace. Pyrite is many times called marcasite in the gem trade. Marcasite is not suitable for gem use, because it powders and may disintegrate into a powder.

References

Barthelmy, David (2004). Pyrite mineral data Retrieved October 6, 2004 from the World Wide Web http://www.webmineral.com/data/Pyrite.shtml. Amethyst Galleries, Inc. (1996) The mineral pyrite. Retrieved October 6, 2004 from the World Wide Web http://mineral.galleries.com/minerals/sulfides/pyrite/pyrite.htm. Chesterman, C.W. (1995). The Audubon Society field guide to North American rocks and minerals. NY: Alfred A. Knopf.

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Sphalerite: A Miners Worst Nightmare by Dustin Ross

Originating from the Greek word sphaleros, meaning treacherous rock, sphalerite has fooled many people in the past with its physical properties (www.mineral.galleries.com). This name was given to sphalerite because miners had a hard time distinguishing it from more valuable minerals like galena (lead sulfide) and acanthite (silver sulfide) (www.mineral.galleries.com). Sphalerite has many wonderful physical properties associated with it, as all minerals do. Sphalerite just happens to share similar isometric structures and related chemistry with a few other minerals. Putting the mineral Sphalerite as the top mineral of a group. Coloradoite, stilleite, tiemannite, hawleyite, and metacinnabar all fall into the Sphalerite Group of minerals, the tetrahedral sulfide group (www.mineral.galleries.com). Many minerals have characteristics that separate them from other minerals. Sphalerite has some attributes that make it stand out among many other minerals. One such attribute is luster; which happens to be sphalerite's best attribute. Sphalerite has a very nice adamantine luster and really sparkles in light. This is due to the minerals high index refraction.

Sphalerite’s hardness is 3.5-4 on the Moh’s hardness scale and its chemical formula is ZnS. Although the streak is often a pale yellow, the streak of sphalerite can be quite misleading. Pure sphalerite streaks white, while impure specimens of sphalerite may streak red-brown (Schumann, 1992). Color varies with this mineral as well. It is often found as a brown-red and is colorless when pure; however, it can be found in green, blue, white, pale gray, yellow (Chesterman & Lowe, 1995). Specific gravity is 4.0, while it has perfect cleavage in six directions (Perkins, 2002). Other properties include conchoidal fracture and its tenacity is brittle (www.mineral.net). Sphalerite will produce a sulfuric rotten egg smell when rubbed hard or dissolved in hydrochloric acid. In addition, sphalerite has a unique electrical ability as a pyroelectric mineral. This means that the mineral will form a slight electrical charge when it is cooled or heated (www.mineral.galleries.com).

Twinning properties of sphalerite are unique as well. It can form a spinel twin, which happens when the tetrahedral crystals twist in the middle and three points will align straight (www.mineral.galleries.com). Sphalerite can be found along side many other minerals. It is most noted to be found along with galena, pyrite, fluorite, calcite, magnetite, and quartz (www.mindat.org). USA, Spain, Peru, Burma, and Mexico are places where sphalerite is most notably found (Chesterman & Lowe, 2002). However, many well-formed specimens are found in the tri-state area. Joplin, Missouri has been known as an area that these nicely formed minerals are found.

Industrial uses of sphalerite are very minimal. Sphalerite is simply the main ore of zinc. Since this mineral is a sulfide, it is often used in making metals like copper, lead, and silver. In a lot of cases, sphalerite is also the main ore of gallium, iridium, and cadmium (www.minerals.net). It can also pose as a filler mineral in the more precious ores such as copper. Moreover, when found in pure forms the mineral has a magnificent sparkle. This mineral has a great use for gemologists. It can be polished and made into a beautiful specimen. In clear form it can be a very valuable mineral. Sphalerite also shows its usefulness in jewelry business. With the high refractive index of 2.37-2.42, this mineral is sparkly and makes a nice addition for a jewelry collector.

References

Chesterman, C.W. & Lowe, K.E. (1995). National Audubon Society Field Guide to North American Rock and Minerals. NY: Alfred A. Knopf.

Perkins, D. (2002). Mineralogy (2nd ed.). Upper Saddle River, NJ: Prentice Hall.

Schumann, W. (1992). Minerals of the World. New York: Sterling Publishing Co., Inc.

Sphalerite: Sphalerite mineral data. Retrieved from http://www.mindat.org on November 1, 2004.

The mineral sphalerite. Retrieved from http://mineral.galleries.com on November 1, 2004.

Friedman, H. (1997). Sphalerite. Retrieved from http://www.minerals.net on November 1, 2004.

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Halides


The Coolest Colored Mineral in the World: Fluorite by Lacey Dreyer

Fluorite is a mineral with vary diverse colors and is one of the most attractive minerals to have in a collection. Fluorite is in the class of halides. In general, Halides are soft, weak and brittle. Many halides will dissolve in water or a solution.

Fluorite has a hardness of 4 and specific gravity between 3.0 and 3.2. It has perfect cleavage in four directions which forms an octahedron. Also, it has a conchoidal fracture. Fluorite is transparent to translucent; it is fluorescent and has a vitreous luster. Fluorite is located in the isometric crystal system and usually found in cubic or penetration twins (Chesterman, 1979). The single refractive index for fluorite ranges between 1.433 and 1.435.

Fluorite comes in many different colors such as deep purple, which is the most famous of the colors. Other colors include blue, green and yellow. Colorless fluorite is rare and is sought after by collectors. Brown, pink, black and reddish orange and in high demand and are hard to find (Amethyst Galleries, 1996). Fluorite can also have colors that are arranged in bands or zones or even be in multiple colors such as green and purple (Minerals-n-More).

The name fluorite is from the Latin word fluere which means it melts easily. The history of fluorite dates back as far as the Roman times. The Romans use to call fluorite Blue John or Derbyshire spar. They used it to make vases and other objects. Fluorite was first called fluorspar by miners and sometimes it is still called that (Minerals-n-More).

Fluorite is also Illinois’ state mineral. It has been mined there since the early 1800’s. This area was called the Illinois- Kentucky Fluorspar Mining District because of the fluorspar-rich region which extends from southeastern Illinois into parts of Kentucky (Reinertsen, 2003). The mining in this area is mostly underground as deep as 1,300 feet. There are also mines located at the surface. In 1942 Illinois became the leading producer in the United States for fluorite. Illinois produce more than fifty percent of the total United States fluorite. In December of 1995 the last mine had to close because it became unprofitable. Fluorite is no longer mined anywhere in the United States (Reinertsen, 2003).

Fluorite is a vital mineral to the nation’s economy because of all the uses associated with it. Fluorite is used in almost anything possible. It is used in manufacturing glass, ceramics, cement and other chemical compounds. NASA uses it for rocket fuel. It is also used to refine fuel for the nuclear reactors in the United States. Fluorite is used in everyday things that humans use such as toothpaste, optical lenses and concrete hardeners. It is also used in plastics, refrigerants, nonstick coatings, lubricants, stain repellents, dyes, herbicides, medicines and anesthetics.

Works Cited
Amethyst Galleries Inc. 1996. (WWW) Fluorite, The Most Colorful Mineral in the World. Available:
http://mineral.galleries.com/minerals/halides/fluorite/fluorite.htm. Retrieved 10/28/04.

Chesterman, Charles W. National Audubon Society Field Guide to North American Rocks and Minerals. Chanticleer Press, Inc. New York. 1979

Minerals-n-More. Gemstones and Jewelry. The Mineral Fluorite. (WWW) Available: http://www.minerals-n-more.com/Flouorite_Info.htm. Retrieved 10/28/04.

Reinertsen, D.L. (2003) Illinois State Geological Survey. (WWW) Fluorite-Illinois’ State Mineral. Available: http://isgs.uiuc.edu/servs/pubs/geobitspub/geobit4/geobit4.htm. Retrieved 10/28/04.

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Halite: My Spice of Choice by Dustin Ross

At the dinner table there is quite often a common phrase said, “Could you please pass the salt and pepper?” However, what really should be said is “can you please pass the halite and pepper?” The term halite comes from the Greek word salt. This is how we have come to know that the halite in the shakers on our kitchen tables is termed salt (www.desertusa.com).

Halite has numerous physical properties. The color is usually a dead give away of the mineral. It is most commonly found in either a clear or white color. However, it may be blue, yellow, gray, pink or purple (Schumann, 1992). It possesses perfect cleavage in three directions forming 90 degree angles (Chesterman and Lowe, 1995). This is what gives the mineral a cube-like appearance. It has a conchoidal fracture and a vitreous luster. The hardness of the mineral is 2 on the hardness scale (www.rocksandminerals.com). It streaks white. Its specific gravity is 2.1, which is considered very light (www.mineral.galleries.com). The boiling point for halite is 1,413 degrees Celsius, while its melting point is much lower at 800 degrees Celsius (www.rocksandminerlas.com). Minerals that are isostructural with halite include galena, alabandite, periclase, and chlorargyrite (Perkins, 2002). The chemical make up of halite is felt through its taste. Halite is sodium (Na) and chloride (Cl) that come together to make salt. Salt is about 39.337% sodium and 60.663% elemental chloride (www.rocksandminerals.com).

Halite, or salt, is found in many places around the world. Sea water contains about 2.6% NaCl and is a big source for salt extraction (www.rocksandminerals.com). Halite is found in many evaporate deposits such as near Searles Lake, California and Salt Lake City, Utah. Several United States cities such as Cleveland and Detroit sit on massive halite deposits that are mined for industrial purposes (www.mineral.galleries.com). Germany and Austria have huge halite deposits as well (Chesterman and Lowe, 1995). Halite is even found in large quantities in Kansas, Lyons and Hutchinson, which are well known for mining halite.

Halite has found many uses in our world as we know it. In fact, our own bodies would not function right with out the mineral halite. As an essential nutrient, vital to all animals of the world. Since our own bodies cannot manufacture sodium and chloride naturally, halite is the supplement for humans (www.rockandminerals.com).

Halite is used in mass quantities for the production of paper. The byproduct of halite is chlorine and caustic soda which is used in the paper making process. A primary use for halite in developed countries that have inclement conditions is for melting ice. Road safety is vastly improved when halite is applied on ice, since halite is a natural de-icer (www.minerals.net). When we use water softeners halite is most often involved. Halite replaces calcium in the water with sodium, which makes the water softer. The industrial realm also uses halite in many ways. It is used to fix and standardize dye batches for textile industries. Halite is also used in many rubber factories to help separate rubber from latex (www.rockandminerals.com).

Halite, better know as sodium chloride or salt, has been involved with almost every form of anthropogenic and biological life on the earth. With out this vital mineral our own bodies would simply not function. We owe our way of life to halite and many other minerals of the world!

References

About Salt. Retrived from http://www.saltsense.co.uk on October 25, 2004.

American Rocks and Minerals. New York: Alfred A. Knopf, Inc.

Chesterman, C.W. & Lowe, K.E. (1995). National Audubon Society Field Guide to North American Rocks and Minerals

Halite. Retrieved from http://www.minerals.net on October 25, 2004.

Halite, the Mineral. Retrieved from http://www.desertusa.com on October 25, 2004.

History of Salt in the United States. Retrieved from http://www.rocksandminerals.com on October 25, 2004.

Perkins, D. (2002). Mineralogy (2nd ed.). Upper Saddle River, NJ: Prentice Hall.

Schumann, W. (1992). Minerals of the World. New York: Sterling Publishing Co., Inc.

The Mineral Halite. Retrieved from http://mineral.galleries.com on October 25, 2004.

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Oxides/Hydroxides


Bauxite by Susan Kelley

Bauxite is a naturally occurring material comprised primarily of one or more aluminum hydroxide minerals plus various mixtures of silica (SiO2), iron oxide (Fe2O3), titania (TiO2), aluminosilicate, and other impurities in trace amounts. The principal aluminum hydroxide minerals found in varying proportions within bauxite are gibbsite [Al(OH)3] and the polymorphs, boehmite and diaspore [both AlO(OH)].

“ Of all bauxite mined, approximately 85% is converted to alumina (Al2O3) for the production of aluminum metal, an additional 10% goes to nonmetal uses as various forms of specialty alumina, and the remaining 5% is used for nonmetallurgical bauxite applications” (Plunkert, 2000). The bulk of world bauxite production is, therefore, used as feed for the manufacture of alumina. “On a world-wide average 4 to 5 tons of bauxite are needed to produce two tons of alumina, from which one ton of aluminum can be produced” (Azom, 2004).

The world-aluminum website tells us bauxite is found in four types of deposit: blanket, pocket, interlayered and detrital. The major bauxite deposits of the world are found in the tropics and in the Caribbean and Mediterranean regions. Today most bauxite mining locations are in the Caribbean area, South America, Australia, and Africa (The International Aluminum Institute, 2000).

Porterfield (2002) reports that the only place in the continental US where it has been economically feasible to commercially mine bauxite ore is near Bauxite, AR. Mining began in 1899 and increased each year, peaking during the WWII years when the need was greatest because German Submarines were sinking the ore ships from Suriname. Alcoa developed and built a Bayer - Sinter plant for processing the bauxite ore into aluminum oxide. The high grade, low silica content bauxite ore is no longer available and the low- grade ore is not economically feasible to process. All the mining and refining plants in Bauxite, AR have been shut down. Alcoa still has a chemical plant there, using shipped in alumina from other refineries (Porterfield, 2002).

Bauxite ranges in color from off-white to deep reddish brown and structurally from soft, earthy material to a well-cemented rock. Many bauxite deposits have an oolitic to pisolitic texture.

Aluminum is silvery white, has a low specific gravity of 2.69, and a low melting temperature. Two reasons for aluminum's versatility are its light- weight, and its strength when alloyed with other metals. Aluminum is easily cast, machined, rolled, forged, extruded, and drawn. Aluminum is efficiently recycled, as the aluminum from used products requires only 5% as much energy as extracting aluminum from bauxite. Major uses of aluminum are aluminum paint, beverage cans, baseball bats, power lines, house siding, boats, and airplanes.

References

Plunkert P.A. (2000). Bauxite and Alumina--2000. Retrieved October 27, 2004 from the World Wide Web < a href="http://www.minerals.er.usgs.gov/minerals/pubs/commodity/bauxite/090400.pdf">http://www.minerals.er.usgs.gov/minerals/pubs/commodity/bauxite/090400.pdf.

AzoM (2004). Bauxite Mining and the Environment. Retrieved October 27, 2004 from the World Wide Web http://www.azom.com/details.asp?ArticleID=1529.

The International Aluminum Institute (2000). Bauxite Mining. Retrieved October 27, 2004 from the World Wide Web http://www.world-aluminum.org/production/mining/.

Porterfield P. (2003) The Bauxite Chapter. Retrieved October 27, 2004 from the World Wide Web http://www.nwla.com/bauxite.

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Hematite by Jonathan Howard

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Magnetite by Jonathan Howard

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Carbonates


Calcite by Lacey Dreyer

Calcite is one of the most amazing minerals found on Earth. It comprises about four percent of the Earth’s crust which would make it one of the most common mineral on the Earth. Calcite can be formed in many different geologic environments and it is a significant part of all three rock types (Amethyst Galleries Inc, 1996).

Calcite has several different colors that range from white to pale shades of grey, yellow to red, green to blue, and brown to black when impure. On Mohs Hardness scale calcite is three (3) and the specific gravity is 2.7. The cleavage is perfect in three directions, forming a rhombohedron and it fracture is conchoidal. Calcite is transparent to translucent and can be fluorescent (Chesterman, 1979). The crystal system for calcite is trigonal and crystal class is bar 3 2/m (Amethyst Galleries Inc, 1996). Another interesting property of calcite is its high birefringence. If a calcite crystal was held over an object or a piece of paper with words on it, the object or words will be doubled. This is caused when a ray of light enters the crystal and splits into two rays, which are slowed at differing rates and thus, traveling at different speeds. When they leave the crystal the beams are bent into two different angles (Amethyst Galleries Inc, 1996).

There are several types of calcite but there are a few that stand out more than others are Dogtooth Spar, Mexican onyx and Iceland Spar. The most common form of calcite is the Dogtooth Spar. It is the most well known of the calcite varieties because of its shape which resembles the canine tooth of a dog. This type of calcite came from places such as Ohio and Tennessee, in USA and England in UK. Mexican onyx, not onyx at all, is a variety of calcite that is used for ornamental purposes. Iceland Spar is another variety that is common among calcite. It is clear fragments of completely colorless calcite. This variety was first found in Iceland in basalt cavities. Most of the Iceland spar that is sold today comes from Mexico (Amethyst Galleries Inc, 1996).

There are several uses for calcite. The most important use is in mineral collections because of the varieties found and the varieties of color that calcite can have. Some people use calcite for healing reasons. Calcite can be an aid to perception, meaning that it will help to see things more clearly and to see reality in a different way. It is also used as a calming stone, which allows a person to look at there life and see if some aspect are in need of change. It has also been said that calcite can be an aid to memory and meditation (EarthBow, 2001). Some of the industrial uses of calcite include the food industry, paper industry, and paint industry, plastic industry which would include things such as PVC pipes, panels and cables. It is also used in adhesives and tooth pastes, in carpets and oilcloths (Hisar).

Works Cited

Amethyst Galleries Inc. 1996. (WWW) The Mineral CALCITE. Available: http://mineral.galleries.com/minerals/carbonat/calcite/calcite.htm. Retrieved 11-8-04.

Chesterman, Charles W. National Audubon Society Field Guide to North American Rocks and Minerals. Chanticleer Press, Inc. New York. 1979

EarthBow. 2001. (WWW). New age crystals, minerals, rocks, gems, stones and their uses. Calcite. Available: http://earthbow.com/crystals/calcite.htm. Retrieved 11-9-04.

Hisar Industry Leader in Micronised Calcite Production. (WWW) Calcite. Available: http://www.hisarmaden.com/eng.htm. Retrieved 11-10-04.

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Vanadates


Vanadinite by Susan Kelley

Vanadinite is lead chlorovanadate, Pb5(VO4)3Cl. Vanadinite is in the phosphate class and the apatite group. Barthelmy (2004) reported that, “vanadinite is composed of 10.79% vanadium, 73.15% lead, 2.5% chlorine, and 13.56% oxygen”. It is usually red while the other members of this apatite group are not. Vanadinite's classic crystal habit is short hexagonal prisms terminated by a pinacoid. Its luster is vitreous to adamantine and it is translucent to transparent. No cleavage is present and its fracture is conchoidal. Vanadinite's hardness is 3 and it has a specific gravity of 6.6+, which is very heavy for a translucent to transparent mineral. It will streak yellowish white and has an index of refraction of 2.39, which is high for a lead mineral.

“The finest Vanadinite is from Mibladen, Morocco, where it occurs as blood-red hexagonal plates and “barrels”. Beautiful crystals also come from Touisset, Morocco; Tsumeb, Namibia; Broken Hill, Zambia; and Cordoba, Argentina. The only significant occurrences of Vanadinite in the U.S. are in the arid southwest. Localities in Arizona include the Apache Mine, Globe district, Gila County; the Hamburg Mine, Yuma County; the Mammoth Mine, Tiger, Pinal County; and the Old Yuma Mine, Pima County” (Friedman, 2000).

Vanadinite is an important ore of vanadium. Vanadium is used in several industrial applications. “Vanadium is used extensively to make alloys for tools and construction purposes. Vanadium is alloyed with iron to make carbon steel, high- strength low-alloy steel, full alloy steel, and tool steel. These hard, ferrovanadium alloys are used to make armour plating for military vehicles and other protective vehicles. It is also used to make car engine parts that must be very strong, such as piston rods and crank shafts. The steel “skeleton' or frames of high-rise buildings and oil drilling platforms must be very strong to support the weight of the building and its contents; vanadium steel has the strength to support such massive weight” (Mineral Information Institute, 2004). Compounds of Vanadium are also used as a mordant in fabric dyeing.

References

Barthelmy, David (2004). Vanadinite mineral data. Retrieved November 6, 2004 from the World Wide Web http://www.webmineral.com/data/Vanadinite.shtml.

Friedman, Hershel (1997 - 2000). The mineral vanadinite. Retrieved November 6, 2004 from the World Wide Web http://www.minerals.net/mineral/phosphat/vanadini/vanadini.html .

Mineral Information Institute (2004). Vanadium. Retrieved November 6, 2004 from the World Wide Web http://www.mii.org/Minerals/photovan.html.

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For more information, contact S.W. Aber, email: abersusa@emporia.edu. This page was created in September 2004 and was last updated November 20, 2004.

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