Turquoise: Gem of the Southwest

For countless cultures around the globe, turquoise has been a coveted stone for many years. It is one of the oldest gemstones used in the making of jewelry, adding a type of beauty that over time has developed associations to certain areas. Paired with silver, it is a stone that has come to be associated with the desert Southwest of the United States through its use in Native American jewelry.

The arid climate of the desert southwest, and the landscape found there, are a natural setting for the formation of turquoise. The stone is most often found in the cracks and crevices of volcanic rock. Since turquoise is what is known as a secondary mineral, it is generally found with other minerals such as copper. It forms when the accompanying mineral is weathered and oxidized, leaving the veins or nuggets of turquoise in its seams. Most of the time turquoise is found at a shallow depth, with the nuggets small in size and of varying shapes.

Over the years, the southwestern part of the United States was an important area for the mining of turquoise. New Mexico is home to what are believed to be the oldest turquoise mines. The gem was collected in both California and New Mexico by Native Americans, using stone tools to remove it from the surface. Before the early part of the twentieth century, New Mexico was also one of the major producers of turquoise. Today, production in the state is far less.

Arizona and Nevada remain important producers of turquoise, even though some of the historic mines in those states no longer recover the stones. A few are no longer producing mines at all.

Two Arizona mines reflect the changing times for the production of turquoise. The Sleeping Beauty mine, located by Globe, ceased mining for turquoise in the summer of 2012. The increased profitability of copper caused the mine owners to concentrate on that mineral instead. Due to this, the price of natural turquoise from the Sleeping Beauty mine has risen.

The Phelps Dodge Lavender Pit copper mine near Bisbee, which closed in 1974, was never a producer of turquoise in the normal sense. Turquoise pulled from the mine was what is humorously called “lunch pail” mined. What turquoise that was removed from the copper veins left the mine in the lunch pails of the miners.

The only Arizona site still producing turquoise through a large-scale mining operation is the Kingman mine, located outside the city of Kingman. Kingman mine is a copper mine and the turquoise is a side product of its mining.

Turquoise is not a side product for the mines in Nevada which uncover its beauty. Over a hundred mines located in the state contribute turquoise to the world market. Most of these sites are in the business of recovering the stones themselves instead of other minerals. Historically, the production has been a significant amount, with one report stating that “total Nevada turquoise production since the 1870s has been estimated at more than 600 tons”.

Turquoise recovered from the mines in Nevada is, for the most part, of high quality. The stones have a hardness and density to them which means little to no enhancement or treatment is necessary for them to be used in fine jewelry. The stones are of a variety of shades, from blue to green and many of them possess the brown or black limonite veining which is referred to as “spiderweb matrix”.

Most of the turquoise mining operations in Nevada, as elsewhere in the US, are small-scale. Some are even seasonal operations, rather than year-round. This is due in part to the remote locations where the stones are found as well as the increased costs of mining.

Some stones of high quality are still found in the US, but much of the turquoise recovered is low grade, not suitable for the making of jewelry without treatment or enhancement. This makes stones previously found in the historic mines more valuable due to their rarity.

Mining, as many other industries, faces renewed challenges in today’s environment. Environmental regulations and increased labor costs all contribute to the changing world of today’s market. In spite of these differences, however, the beauty of the stones are still a lure most of us cannot resist.

Resources:

http://www.turquoiseguide.com/articles/turquoise/sources/united-states.htm

https://en.wikipedia.org/wiki/Turquoise#Properties_of_turquoise

https://www.silverinstitute.org/site/silver-essentials/silver-in-history/

http://www.thegeozone.com/treasure/new_mexico/history/nm_history6.jsp

http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/sp14-95/turquoise.html