Jake's Big Three Green Gem Preference:
Jadeite Jade, Alexandrite, Emerald

by

Jacob Bray


A Student Presentation from
Emporia State University
Earth Science Department


This page was created as a student project at Emporia State University in the Spring 2003 semester. The project was in partial completion of an online Gemstones and Gemology course.



Images taken from:
http://mineral.galleries.com/minerals/silicate/jadeite/jadeite.htm
http://mineral.galleries.com/minerals/gemstone/alexandr/alexandr.htm
http://awesomegems.com/emerald-5.html#top
Introduction

When you think of gemstones, what comes to mind first? For me it's, “Is that expensive?” This is followed quickly by other questions such as, "Is it natural?" "Where does it come from?" "Is it rare?" Of course there’s a reason for my questions. I have always been curious, to say the least, about the value, origins, and rarity of gemstones. There is just something about the look, the feel (yes, the feel), and the mystic of beautiful colored gemstones. It just amazes me that something that could fit in the palm of your hand, could be worth so much money. Add to that the physical and cultural history of the gem and you have my attention very quickly.

Of course some gemstones are large, but the majority of gems bought and sold are very small. Some not much larger than a grain of sand. The largest gems, like the size of a golf ball or bigger, are so rare they are in museums or the hands of private collectors. What other items can lay claim to that? I can’t think of many. These large gems really blow my mind and when you try to put a monetary value on something like this it becomes nearly impossible. Now think of all the different types of gemstones on Earth. With colors, sizes, and composition there are literally hundreds of possibilities! If you have a certain style in mind, rest assured that you will find your fancy. If it is a color you desire, again we have you covered. All colors imaginable are available. Sometimes several colors are found in the same stone, as is the case with a gem we will cover later in this web page.

So what I’m getting at is this, although for the most part gemstones are rare, they are available and cover all price ranges! I like many, but three of my favorites are the subjects of this webpage. I have devoted this web page to jadeite jade, alexandrite, and emerald, because of their rich green colors, history, value, and special phenomena.

Before we go further, we need to define one very important thing. A gemstone according to Mr. Walter Schumann, via his book titled Gemstones of the World, includes minerals, mineral aggregates, mineraloids, and rocks. I will not discuss organic or synthetic materials but they should not be excluded from the wide range of decorative objects. Gemstones are naturally occurring and mostly inorganic in origin. To be considered a valuable gem, the substance must have beauty, but also it can have an unusual optical phenomena, high hardness, interesting inclusions, rarity (but not to rare), and some ornamental value. Gemstones were important to humans past, and still today. Important enough to dedicate an internationally known science that studies all things gem. This science is known as gemology.


Table of Contents


Fine Imperial jadeite jade.
Image taken from:

http://www.palagems.com/burma_jade_pt2.htm

This beautiful necklace sold in 1997
for 9.3 million dollars. Image taken from:

http://www.palagems.com/
burma_jade_pt2.htm


Alexandrite in natural light.

Image taken from:
http://www.awesomegems.com

The sale price for this
1.76 ct.is only $20,416.00!

Image taken from:
http://www.awesomegems.com


Emerald crystal, 2.67 ct.
Image taken by Susie Aber.


Emerald crystal, 2.67 ct.
Image taken by Susie Aber.



Natural purple jadeite
jade from Turkey.
Image taken J. Bray.

Jadeite

Jadeite is a mineral aggregate, meaning it is made up of more than one mineral (Schumann). Jadeite jade refers to one of two minerals called jade, jadeite jade and nephrite jade (http://www.webmineral.com/data/Jadeite.shtml). Nephrite jade is completely different; it is an amphibole while jadeite is in the pyroxene group of inosilicates (http://webmineral.com/data/Actinolite.shtml).

Jadeite is extremely tough, actually stronger than steel (Schumann). This is due to the interlocking fibers within jadeite. A flame test will produce a yellow burn (Schumann). Jadeite occurs in several locations around the globe, namely Burma (Myanmar), Japan, Canada, Guatemala, Kazakhstan, and Russia. Chinese jade is typically jadeite imported from Myanmar.

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Physical characteristics of Jadeite

Information below taken from http://www.webmineral.com/data/Jadeite.shtml:
Chemistry NaAlSi2O6
Class Silicates
Color Many consider jadeite only green,
but there is a diverse color
collection of white, pale bluish,
grayish green, or pale purple
Luster Vitreous to waxy
Transparency Generally opaque to translucent
Crystal System Monoclinic; 2/m
Habits Generally massive. Crystals of any size are rare.
Cleavage Poor in 2 directions at or near 90 degrees.
Fracture Splintery to uneven.
Hardness 6.5 to 7
Specific Gravity 3.3 to 3.5
Streak White

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Jewelry and Ornamental Use

Jadeite is a multi-use stone. In ancient times jadeite was formed into shape and used as tools, an example would be an axe. This is why it may is known as the "axe stone." Jadeite's tough tenacity makes it useful for this purpose (Schumann). Jadeite carvings are also important in the world of religion. Buddha carvings were used in religious ceremonies and decorated places of worship for over 2000 years. Jadeite is still carved and used for this purpose today, as well as being cut en cabachon to be used in rings and pendents. It's often carved and used as a bangle. The most valuable jadeite is known as Imperial Jade (Schumann). It is an emerald-green translucent to almost transparent and can command a very high price. Some ancient carvings have in auction topped the million dollar mark. With the increase in translucency and eveness of color the value soars. The rarest of colors is a lavender to purple color. Jadeite is often soaked in wax to improve appearance.

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The Mining of Jadeite

The largest jadeite deposits are in upper Burma (Myanmar). Smaller deposits are found in Japan, Canada, and Kazakhstan. The mining of jadeite is typically via manpower, meaning that men work river beds and remove large boulders of jadeite (Schumann). Current technology has yet to be utilized. Once a large boulder is removed, a small area is cut and polished to act as a window to what is inside. This is all that the buyer will see. The buyer will take the boulder to a processing area and only then will the buyer see exactly what was purchased. The buyer can overpay, which is always passed on to the consumer by inflated prices. Miners earn very little for their high labor work (www.palagems.com).

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Alexandrite in natural light.

Image taken from:
http://www.awesomegems.com

Alexandrite

Alexandrite is a gem variety of the mineral chrysoberyl. It was named after the Russian Czar Alexander II and was discovered fairly recently in 1830. The discovery site was in the Ural mountains in Russia. This site has since been worked out. The cool thing about alexandrite is it's natural ability to change color. Yes, change color!. In daylight alexandrite will take on a green color, while in artifical light the stone will change to red. Iron and chromium are responsible for the color. This color changing stone is the reason alexandrite fetch's such high prices in the gem trade. If clarity and the percent color change are both good, stones can go for thousands of dollars. I recently ran across a .98 ct stone with a 60% color change and average to good clarity for $4,900.00! Higher grade stones will run you even more! Even more rare, is an alexandrite that displays the cat's-eye effect. This variety can comand an even higher price! Alexandrite is one of the most expensive gems and can rival fine diamonds carat for carat! The largest cut alexandrite weighs 66 ct and is housed in the Smithsonian Institution in Washington D.C. The largest ever found was found in Sri Lanka and is a whopping 1,876 ct.

Alexandrite's host rock is granite pegmatite, mica schist, and placers (Schumann). The color change effect is best seen in thick stones. Alexandrite placed in a ring should be worn with caution, as it can break or crack easily (www.webmineral.com). While one should showcase the rare and beautiful stone, you should also be very careful not to bump a hard surface and to keep the stone away from a heat source as it can be damaged!

The sale price for this
1.76 ct.is only $20,416.00!

Image taken from:
http://www.awesomegems.com

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Physical characteristics of Alexandrite

Information below taken from http://www.webmineral.com/data/Chrysoberyl.shtml:
Chemistry BeAl2O4
Class Oxides
Color Golden-yellow, green-yellow, green, brownish, red
Luster Vitreous
Transparency Transparent to opaque
Crystal System Orthorhombic
Habits Thick tabular, intergrown triplets
Cleavage Good in 1 direction, poor in 2 others
Fracture Weak conchoidal, uneven
Hardness 8.5
Specific Gravity 3.70 to 3.78
Streak White

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Jewelry and Ornamental Use

Alexandrite is often used in some form of jewelry, such as a ring, pendant, or earrings. When faceted, it is often found in a step cut or the brilliant cut. Cabachon cuts can be found too. The process of turning a low grade stone into a higher grade stone in not completely effective with alexandrite, as it is with many other gems. Synthetic alexandrite is very common on the market today.

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The Mining of Alexandrite

Alexandrite is mined in only a handful of locations. The mines in the Urals of Russian are worked out, so mining has shifted to other locations (Schumann). Key producers included: Sri Lanka, Zimbabwe, and since the 1980's, Brazil. Also, adding to the supply is Burma (Myanmar), Madagascar, and Tanzania. Here again we see a stone that is extracted from the Earth via manpower or primitive means. There are few mechanized means to mine alexandrite in these locations.

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Emerald


Emerald, 2.67 ct.
Image taken by Susie Aber
Emerald is the gem variety of the mineral beryl. The name emerald is derived from the Greek word meaning "green stone" (Schumann). At one time the name emerald most likely consisted of all green stones (Schumann). Today only a certain shade of green in the mineral beryl is called emerald. The most valuable emerald is a deep green color with a hint of blue. Like many natural gemstones the color saturation and clarity are important in emerald. A good even color distribution will increase value; as will high clarity. The emerald is considered to be a very dirty stone, meaning that only very fine specimens are transparent. Many are cloudy, milky and thus, dirty looking. This is caused by inclusions within the mineral. Therefore, odd as it may sound, inclusions can increase the value because it proves the stone is natural (Schumann)! Fine large emeralds are rare and command high prices (Schumann).
The coloring agent in emerald is chrome (Schumann). "Emerald" colored with vanadium is technically not emerald, and should be called green beryl (Schumann). Emerald is a brittle stone and care should be taken when wearing and cleaning as it may crack or break. Emerald has strong green to blue-green pleochroism which can also help to detect an imitation or synthetic. The emeralds physical properties differ slightly from source area to source area.

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Physical characteristics of Emerald

Chemistry Al2Be3Si6O18
Class Silicate (Cyclosilicate)
Color Emerald green, green, slightly yellowish-green
Luster Vitreous
Transparency Transparent to opaque
Crystal System Hexagonal
Habits Crystals common, usually six-sided prisms
Cleavage Indistinct, one direction
Fracture Small concoidal, uneven, brittle
Hardness 7.5 to 8
Specific Gravity 2.67 to 2.78
Streak Colorless.

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Jewelry and Ornamental Use

Emeralds are used for all types of jewelry from rings to earrings, and many cuts are utilized. Because emeralds are brittle, a special cut is often used, called the emerald cut. Oval, tear, brilliant, and princess cuts are also used to facet emerald. For cloudy, highly included stones, en cabachon is the best cut. Carvings are another way to show off the brilliant green color of emerald and have been used for centuries. Emerald is another stone that is often soaked in wax then polished to improve appearance.

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The Mining of Emerald

Emerald deposits are found in biotite schists, clay shales, and in limestones (www.webmineral.com). Mining is directly from the host rock, where the emeralds have formed within cavities or small veins of rock. These areas are located in Columbia, Brazil, and South Africa, with Columbia being a major producer. Less than 30% of all mined emeralds are gemstone quality. Mining techniques are for the most part primitive due to the host country.

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Conclusions

I have tried to cover briefly three of my favorite gems. My intent was to cover important information as it pertained to all three gems of my choice. In my opinion jadeite, alexandrite, and emerald are some of the most beautiful stones nature has to offer and due to this beauty they are very valuable. The prices are driven by our own personal preferences and as fads and preferences change, so will the value of my big three. They may increase or decrease, but for me, I will always view them as beautiful and valuable in their own special way!


References and Addtional Sources


Return to student webpages.

Date of creation: April 15, 2003. Copyright 2003 Jake Bray All rights reserved.