WorldWide Drilling Resource

The Traditional December Gem by Harry W. Short, Engineering Geologist Turquoise, the December birthstone, could be substituted for zircon or tanzanite, but we will stay with the traditional gem- stone which has been mined since about 6000 B.C. Treasured for its distinctive blue color, turquoise has been used for jewelry by Native Americans and many Mexican Indian Tribes from about 200 B.C. The Indian-style jewelry is relatively new and was unknown before 1880. The story goes that a trader had a Navajo craftsman make turquoise jewelry combined with coin silver. Prior to this time, turquoise was made into beads, carved, and mounted in inlaid mosaics. The name turquoise may have come from the French word “Turquie” meaning “Turkey” because in early history it was believed it came from that country. Turquoise was transported to Europe through Turkey and this could have been the derivative of the name. Others thought the gemstone came from France because they described it as “pierre turquin”, meaning dark, blue stone. Early turquoise gemstones likely came from one of the world's two oldest and most famous mining areas in Persia (Iran) or the Sinai Peninsula in Egypt. Turquoise found in Persia for thousands of years was of good quality and “Persian Turquoise” became tantamount with excellence. Today, the finest gemstone turquoise comes from Iran and Tibet. Turquoise, a hydrated phosphate of copper and aluminum, forms when rain or groundwater percolates through sediments and/or rock containing aluminum and copper minerals or compounds. It has a waxy to dull luster, a hardness of 5 to 6, and a specific gravity of 2.6 to 2.9. It is noted for its bright, sky-blue color, but it can also be green and yellowish gray. Turquoise is massive in form, crystals are rare, and it is commonly found in nodules and veins. Gemstone turquoise occurs in the dry, arid climate in the western United States. Nevada was a major turquoise producer from the 1930s until the 1980s. New Mexico produced turquoise into the 1920s, but has been long surpassed by Nevada and Arizona. Arizona is now the leading state in turquoise production. Colorado has only one commercial turquoise mining area according to the U.S. Geological Survey. In California, old mining tools have been found dating back to the pre- Columbian Native Americans in gemstone production areas. Significant deposits of turquoise have been found in San Bernardino, Imperial, and Inyo Counties. Harry Harry Short may be contacted via e-mail to michele@ worldwidedrillingresource.com Carved turquoise from Arizona courtesy U.S. Geological Survey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orldWide Drilling Resource ® DECEMBER 2015