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Roger Weller, geology instructor

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Turquoise
by Angel Sherman
Physical Geology
Fall 2009
    
  

                       Bisbee Mines & Turquoise 

 

Bisbee a quiet copper mining town was founded in 1800.  They mined copper, silver, and gold.  Founded in the rural Mule Mountains just Southeast of Sierra Vista, Bisbee became home to many miners from around the country.  Mining became a very popular source of work in the early 20th century.  The population of Bisbee grew rapidly, opening the suburbs known today as Warren, San Jose and Lowell.  As time went on so did the mining in the Copper Queen Mine.  This is one of the biggest and most well known mines in the Southwestern part of the United States.  The Copper Queen Mine had a 23% ore body, where as other mines during that time ran a 2% or 3% ore body (Wikipedia).  Not only did Bisbee discover copper, silver and gold, but also you could find minerals such as Cuprite, aragonite, wulfenite, malachite, azurite, and galena (Wikipedia).  These are just a few of the minerals you could find underneath the town.  In the late 1800s the copper that was mined in Bisbee produced 750 thousand tons of copper.  This was about 60% of the entire United States production.
 

Other than copper, silver and gold that were commonly mined in Bisbee, you can also find turquoise.  Turquoise is a blue green mineral that is a phosphate of copper and aluminum.  The chemical formula for turquoise is CuO.3Al2O3.2P2O5.9H2O (Weller).  This stone has a hardness of a six so it falls between quartz and apatite.  The blue color comes from the copper and the green color comes from iron (Gem by Gem).  Although this mineral is considered a gemstone it has a rather opaque look to it.  “Often considered the holy stone, the turquoise is an ancient mineral that keeps finding itself in our fashion today.  The earliest recorded finding of any turquoise deposits was dated back to 3000 B.C. where a deposit was found in the Persian Kingdom” (Gem by Gem).  My great grandmother who was a Cherokee Indian used to tell me that the more blue the stone looked the higher quality, but if the turquoise had more green in it the value was no good.













 

http://skywalker.cochise.edu/wellerr/minbis/turquoise/6bzb-turquoise-polished1z.jpg
 

The Turquoise that was found out of the Bisbee mines was nicknamed Bisbee Blue. “It was found as the miners had to remove some conglomerate rock to get to where the ore body was located.  In these “waste” rocks as they were called was the turquoise.  It was found in vein or nugget form” (Bisbee Turquoise).  The colors ranged from a light blue to a brilliant bright blue.  Maybe even a little green turquoise was found.  According to the Durango Silver Company, a lot of the Bisbee turquoise was recovered by what was known as “dumpers.”  These dumpers would go through all the waste rock from the mine and hunt for the turquoise to take back home (Bisbee Turquoise).  Even though this was illegal, they did it anyways.  Other than the dumpers, there were the truck drivers and the security guards that also took off with this precious gem.  Much of the Bisbee Blue you see today was recovered by the “dumpers.”

 

http://skywalker.cochise.edu/wellerr/minbis/turquoise/6bzb-turquoise1a.jpg

 

Turquoise can be used for many different uses.  The most common that you see is for jewelry.  Turquoise can be used for necklace pendants, rings and pins.  These are beautiful elegant pieces of jewelry that can be made of Bisbee Blue.  After being polished many of the imperfections of the turquoise are removed or hidden within detail.  The darker the blue the richer the piece and quality, and the lighter or more green the color; the piece may have lesser quality.  Most of the turquoise jewelry that you see today has some imperfections inside like the picture below.  Those are veins of the copper or iron that the turquoise was a part of.  Even though the picture below is of a polished piece there are many pieces that are not polished and you can see the conglomerate rock that the Bisbee Blue set in.  The Native Americans that are found in this area such as the Navaho made simple jewelry out of the turquoise.
 

 http://skywalker.cochise.edu/wellerr/minbis/turquoise/6bzb-turquoise-cab3.jpg

 

Many of the mines today that opened in the early 20th century are no longer in use.  And that includes the Bisbee mines themselves.  Even though mining ended around 1950, Bisbee still thrives today and has a rich culture and history.  Many of the turquoise shops that used to be open to sell the infamous Bisbee Blue are no longer open due to the slow decline in the retrieval of the turquoise.  But you can still find Bisbee Blue being sold in some of the shops downtown.  Bisbee was known around the world for their copper mining and turquoise exposure. 

 

 

 

Sources:

http://en.wikipedia.org/wiki/Bisbee,_Arizona

http://en.wikipedia.org/wiki/Copper_Queen_Mine

http://www.gemstone.org/gem-by-gem/english/turquoise.html

http://www.bisbeeturquoise.com/More-Bisbee-Turquoise-Info.htm

http://skywalker.cochise.edu/wellerr/mineral/turquoise/mineral-prop.htm