Colorado Minerals - Mineralogy Final Project

by

Erin Allen

http://www.emporia.edu/earthsci/amber/go336/allen

This webpage was created as an assignment in a mineralogy course at Emporia State University in November 2006.


Table of Contents


Introduction

As of 2003 there have been over 770 minerals found and catalogued in Colorado (Matthews et al., 2003). Many of these minerals valued as ore deposits are located in what is called the mineral belt (See Figure 1). The belt runs from the northeast to the southwest through the Rocky Mountains and is from 10 to 60 miles wide (Matthews et al., 2003). This mineral rich belt stretches from Boulder to the La Plata Mountains just north of Durango. and was created 75 to 20 million years ago when igneous intrusion and volcanic eruptions deposited over the landscape in a lineament (Matthews et al., 2003). The mineral belt is home to many of the famous mining towns of Colorado. Some of these towns have since been exhausted of their mineral deposits and abandoned. Other old mining towns have become thriving mountain ski towns by adapting to a new economic base. In order for many of these towns to stay alive they have resorted to skiing, snowboarding, and gambling to attract tourists to the region. These include places like Central City, Crested Butte, Telluride, Breckenridge, Aspen, and Silverton.

In 2005, the economy of Colorado was enhanced by $1.52 billion dollars in non-fuel minerals (Cappa et al., 2006, http://geosurvey.state.co.us/portals/0/MMF2005.pdf, p. 1-2, 39). One billion of this was made in gold, silver, molybdenum, uranium, and vanadium (p. 1-2, 39). The $520 million was attributed to industrial minerals like gypsum and the minerals that make up sand, gravel, and cement deposits (p. 1-2, 39). Colorado ranked ninth in the United States in non-fuel minerals last year (p. 1-2, 39).


Figure 1. The blue area is the extent of the Colorado mineral belt,
where most of the economically important minerals in Colorado are mined.

Image taken from:
www.colorado.edu/GeolSci/Resources/
WUSTectonics/LaramideVolcanics/Geography_2.htm

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Important Colorado Minerals

According to a Colorado Geological Survey Fact Sheet on Colorado Minerals (2004)
, non-fuel minerals are divided into metals and industrial minerals (http://geosurvey.state.co.us/portals/0/Mineral%20Fact%20Sheet%202004.pdf). The metals occur within minerals such as molybdenum in the mineral molybdenite or alone as native elements such as gold and silver (http://geosurvey.state.co.us/portals/0/Mineral%20Fact%20Sheet%202004.pdf). Industrial minerals include gypsum, as well as the mix of minerals mined for sand and gravel. This webpage will feature some of the non-fuel minerals that Colorado is especially known for either because of their quality, quantity, or size.

Rhodochrosite is Colorado's State Mineral!

Image taken by Erin Allen.

Colorado rhodochrosite is important and world renowned because of specimens showing exceptional clarity, color, size, and rarity. It is the state mineral and found in 18 Colorado counties (http://geosurvey.state.co.us/Default.aspx?tabid=73). The Sweet Home Mine in Alma, Colorado is the largest rhodochrosite producer in the state and has yielded specimens worth some $100,000.00. Rhodochrosite became the Colorado state mineral in 2002, thanks to the efforts made by Platte Canyon High School earth science students (http://jghist.tripod.com/Geology/projects/rhodochrosite/rhodochrosite.htm). Platte Canyon High School is located in Bailey, Colorado, which is a small mountain town southwest of Denver. The image above was photographed in the Denver Museum of Nature and Science and is called the Alma King, because it was extracted from the mine in Alma (http://geosurvey.state.co.us/Default.aspx?tabid=300). According to this Denver Museum, it is considered the largest and finest rhodochrosite crystal in the world.

For more information, read a story, Sweet Home Mine Rhodochrosite Wall at the Denver Museum of Natural History, written by Jack A. Murphy, was featured in the July, 1997 journal, Rocks and Minerals, and online through Look Smart, http://www.findarticles.com/p/articles/mi_m0GDX/is_1997_July/ai_53289746.

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Aquamarine is Colorado's State Gemstone!

Image taken by Erin Allen.

Aquamarine has been Coloroado's state gemstone since 1971 (http://geosurvey.state.co.us/Default.aspx?tabid=301). It was a result of the efforts of various mineral clubs around the state, such as http://www.facetersco-op.com/zabinski/Clubs/Colorado.html. Aquamarines are most abundantly found on Mount Antero and Mount White in Chaffee County and these two sites are some of the most famous places for producing quality aquamarines (http://geosurvey.state.co.us/Default.aspx?tabid=74). Both mountains are 13,000 feet in elevation or higher. Recently an amateur rockhound found the largest cavity of aquamarine containing rock ever discovered in North America on Mount Antero. The specimen pictured above is from this rock cavity, which measured 37 by 25 inches and is located in a pocket at 12,500 feet (http://www.dmns.org/main/en/General/Exhibitions/Content/aquamarine.htm).

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Colorado Mines Diamond!

This diamond is from Kelsey Lake Mine, Colorado.
Image taken from:
http://www.learngoldprospecting.com/
index.cfm?var_file=gem-collecting.htm

Until recently, diamond has not been associated with Colorado, but in the past ten years, diamond mining along the Colorado and Wyoming border has contributed a fair share to the state economy. This region is called the state line district and is now known for a minimum of 40 kimberlite pipes (Hausel, http://www.wsgs.uwyo.edu/metals/placerDiamonds.aspx). The Colorado Geological Survey newsletter, Rock Talk, featured Colorado diamonds in the 1999 publication, which can be found online http://geosurvey.state.co.us/pubs/rocktalk/rtv2n3.pdf.

Kimberlite and lamproite pipes are where diamonds are recovered. In 1996, the Kelsey Lake mine in the state line district began mining on a commercial scale and Archers Poudre River Resort website called this the only commercial diamond mine in the United States (http://www.poudreriverresort.com/prospecting_for_placer_diamonds.htm). In 1997, the Kelsey Lake Mine produced a 28.18 carat yellow diamond making it the fifth largest ever produced in the US (Hausel, http://www.wsgs.uwyo.edu/metals/placerDiamonds.aspx). After it was cut and faceted, the Colorado diamond weighed in at 16.87 carats, making it the largest American faceted diamond (Archer, (http://www.poudreriverresort.com/prospecting_for_placer_diamonds.htm).

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Gypsum: Variety named Desert Rose

Image taken from:
http://en.wikipedia.org/wiki/Gypsum

Paradox Valley is located in southwestern Colorado has the largest evaporite deposits in the state but is on land being proposed as a Wilderness Area (http://geosurvey.state.co.us/pubs/wilderness/paradox_web.pdf. However, the gypsum has not been mined because transportation costs would outweigh profits (Matthews et al., 2003). Eagle Basin near Gypsum, Colorado is located near a viable transportation corridor and has mined gypsum for years (http://geosurvey.state.co.us/Default.aspx?tabid=106). The city of Gypsum is just off of Interstate 70 and near a major railway connection, making transportation quick, easy, and affordable. The Eagle Basin deposit is Pennsylvanian in age and contains a thick gypsum layer and gypsum has many important uses in industry (www.emporia.edu/earthsci/amber/go336/gypsum.htm).

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Gold

Image taken by Erin Allen.

The first major gold deposits found in Colorado were in 1858 in Cherry Creek (Matthews et al., 2003). This discovery lead to the Pikes Peak or Bust gold rush in the 19th century. Most gold found in the Denver area was in small in portion and exhausted fairly quickly. The Cripple Creek mining district has produced half of all gold found in Colorado over the years. Today, gold is mined at the Cresson Mine by the Cripple Creek and Victor Mine company in Teller County and at the Golden Wonder Mine in Hinsdale County (http://geosurvey.state.co.us/portals/0/MMF2005.pdf, p. 44). The Cresson Mine is the most productive gold mine in the state's modern history (http://coloradomining.org/COMiningFacts.html. "Colorado is currently the 4th leading gold-producing state in the U.S., behind Nevada, Utah, and Alaska, respectively" (p. 43). This is good for the local economy because the gold prices and production are both on the rise in recent years. More gold information can be found at the Colorado Geological Survey site, geosurvey.state.co.us/pubs/rocktalk/rtv6n2.pdf.

**FUN FACT** The dome of the Colorado state capitol building is plated in 24 carat gold leaf and can be seen at www.colorado.gov/dpa/images/capitol_front.gif.

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Molybdenum is extracted from the mineral molybdenite.


Image taken from:
http://www.crystalradio.net/minerals/ index.shtml

Molybdenum is a metallic element (MO) extracted from the mineral molybdenite, which is pictured above. This is Colorado's most important non-fuel mineral because 54.4% of the $1.52 billion dollars generated among non-fuel minerals last year is credited to molybdenum (http://geosurvey.state.co.us/portals/0/MMF2005.pdf, p. 39). While a 2004 Colorado Geological Survey report ranked Colorado second to Arizona in molybdenum production in the United States (http://geosurvey.state.co.us/portals/0/Mineral%20Fact%20Sheet%202004.pdf), a 2005 report stated Colorado was now the leading MO producing state (http://geosurvey.state.co.us/portals/0/MMF2005.pdf, p. 41). In Colorado, molybdenum comes from the Henderson Mine near Empire, Clear Creek County (Matthews et al., 2003), and the Climax Mine located near Fremont Pass in Lake and Summit counties. The Henderson Mine and Mill are operated by Climax Molybdenum Corporation (http://coloradomining.org/COMiningFacts.html). Molybdenum is mined 3,000 feet below the surface at the Henderson Mine and moved along an underground conveyor belt that takes it ten and a half miles, crossing under the Continental Divide, to a processing plant in Summit County Colorado (http://geosurvey.state.co.us/portals/0/MMF2005.pdf, p. 42). In 2005, 32 million pounds were produced at this mine (p. 42). Molybdenum is used as an alloy to strengthen and prevent corrosion in stainless steel, specialty steels, and cast iron (p. 42). While it has many other uses, it is a lubricant found in automotive oils and greases to reduce friction between metal parts (p. 42). More information can be found at http://geosurvey.state.co.us/pubs/rocktalk/rtv4n3.pdf.

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Titanium is primarily extracted from titanium dioxide minerals.


Image taken from:
nl.wikipedia.org/wiki/Titanium

Titanium is a metallic element found in minerals such as rutile and ilmenite, and more specific information can be read at Wikipedia, http://en.wikipedia.org/wiki/Titanium. Colorado has the largest titanium resource in the U.S. (http://coloradomining.org/COMiningFacts.html), and the world’s largest single resource site is in the White Earth Project in Gunnison County (Matthews et al., 2003). It has not become a mine yet, because companies are still exploring the economic feasible of mineral extraction. Titanium is used for jet engines, airframes, space and missile applications (http://coloradomining.org/COMiningFacts.html). Denver is home to the world headquarters for the largest manufacturer of architectural titanium.

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Uranium


Image taken from:
http://alt-e.blogspot.com/2005_06_01_alt-e_archive.html

Uranium is used for electrical generation at nuclear power plants and is a naturally occurring element found in all rock, soil, and water in trace amounts (http://en.wikipedia.org/wiki/Uranium). Uranium minerals include uraninite (aka pitchblende), autunite, uranophane, torbernite, and coffinite (http://en.wikipedia.org/wiki/Uranium). Colorado ranks third in uranium reserves, with Wyoming and New Mexico ahead (geosurvey.state.co.us/portals/0/MMF2005.pdf, p. 33). The Cotter Corporation had uranium mines near Canon City and in the west, Colorado Plateau; although these were among the oldest uranium mines in the U.S., the company closed all mines in November 2005 because they were no longer profitable (geosurvey.state.co.us/portals/0/MMF2005.pdf, p. 33-34). An interesting fact is that Colorado uranium was used in the Nobel Prize winning radioactive research done by Madam Curie and her husband Pierre (Matthews et al., 2003).

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Amazonite and Smoky Quartz

Image taken from:
http://www.collectorsedge.com/gallery/index.html

Amazonite is abundant in Colorado. It is mostly found in Park, Teller, and El Paso Counties, with famous specimens in museums worldwide from the Pikes Peak region (geosurvey.state.co.us/portals/0/MMF2005.pdf, p. 53-54). Colorado is known for the bright green-blue specimens and extremely popular among collectors and for jewelry purposes. However, this mineral is not as important for the overall Colorado non-fuel mineral economy, but the USGS ranked Colorado as the 10th leading gem producing state in 2005 (geosurvey.state.co.us/portals/0/MMF2005.pdf, p. 53).

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Other Notable Colorado Minerals

Other minerals mined in Colorado are important for different reasons and most are used for gem stones (geosurvey.state.co.us/portals/0/MMF2005.pdf, p. 53-54). These include garnet, topaz, tourmaline, rock crystal quartz, smoky quartz, rose quartz, amethyst quartz, turquoise, peridot, sapphire, and zircon. In 2005, the value of gem production in Colorado accounted for $280,00.00, down from the year before at $360,000.00.

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Colorado's Natural Fuel Resources

Colorado's energy resources, including coal, oil, and natural gas, are important to the economy and are widely abundant in throughout the state. While these are not strictly speaking minerals, the public perception is that they are mineral resources.

Coal

Coal is a widespread mineral and underlays 29,600 square miles or 28% of the total land area. The coal in Colorado is especially valuable because of its low sulfur and mercury content. Local power plants burn 45% of the coal mined in Colorado, and the rest is shipped to other states. Most of the coal production is from the northwest part of the state. Coal mining and production information can be found at

Oil and Natural Gas

The second oil field established in the United States was located near Canon City, Colorado. 42 of the 64 counties in Colorado have produced oil, and 39 have produced natural gas. In 2005 oil and gas brought in $9.29 billion dollars to theColorado economy. Since 2002 the gas production in the state has been on a steady rise, while the crude oil is showing a decline in production. Oil and gas production information can be found at

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Conclusions

Colorado is very dependent upon the minerals that can be found within its borders for its economic well being. These minerals were key in bringing settlers to the state in 1858 and developing many of Colorado's mountain towns. Minerals will continue to be important for Colorado because of the revenue they are capable of generating. However, the people of Colorado need to learn from the past and try to make to best of the finite supply available. Towns need to have a dynamic economy and not rely on one mineral to support their well being. Colorado has a very important role in balancing the economic advantages with the stablity of the environment and the approprite extraction of its resources.

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References

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Return to Mineralogy student webpages, www.emporia.edu/earthsci/amber/go336/webpages.htm.

Webpage created 11/2006. Copyright 2006 Erin Allen.