July 9, 2014 The rich story of turquoise
The allure of the gemstone turquoise has attracted people for more than 75 centuries. Interestingly, humans are not the only ones attracted to the blues and greens of turquoise — some insects favor it too.
Turquoise is a French word that means Turkish stone. The Turks brought it to Western Europe from Iran. The Moors of Spain also treasured turquoise—they sourced it from North Africa. The ancient Egyptians were the first civilization to use turquoise as early as 5500 B.C.
The Pueblo peoples of the American Southwest began to mine turquoise early in the sixth century A.D. Turquoise was used for religious and ornamental purposes. The Navajos once used it as a currency. The Apaches attached a small piece to their bows, believing it enabled their arrows to fly true. And the Zunis of western New Mexico valued it most of all—a string of turquoise beads was said to be worth at least several horses.
Turquoise is a blue-green mineral that almost exclusively comes from arid lands. It is most abundant in dry, copper-rich regions of America: Nevada, Colorado, Arizona and New Mexico. It also occurs sporadically in the Mexican states of Sonora and Zacatecas, California’s Mojave Desert, western Texas and Utah.
Rare deposits from humid climates have been found in Alabama and in southern Virginia (the site of the world’s only known crystal).
Turquoise is also found in Peru, Australia, Turkistan, Iran, Siberia, China, Ethiopia, Germany and the Sinai Peninsula. Today, mining is restricted to Iran, China and the American Southwest.
The mineral turquoise results from chemical and physical processes associated with weathering of igneous parent material and takes at least hundreds of thousands but more likely millions of years to form.
Deposits are usually within 100 feet of the Earth’s surface.
The deeper the shade of blue the more copper the turquoise contains. On the other hand, if the turquoise is rich in iron the mineral will display beautiful shades of green.
When turquoise is first extracted from the ground it contains water. As the water evaporates the blue-green stones turn a lighter shade. Low-grade turquoise is porous and when all the water is depleted from the stone it turns bone white—often referred to as chalk.
About 10 percent of turquoise mined today is gem-grade.
New Mexico is home to the Cerrillos/Tiffany mine, the most famous mine in the American Southwest. Turquoise remains the crown jewel of this region and renowned Native American artists like Ray Tracey, Angle Reano Owen, and Carlton and Julie Marie Jamon design and create magnificent jewelry.
Turquoise is a multi-billion dollar industry for the state of New Mexico.
New Mexico is also home to two species of harvester ants legendary both for delivering stings that deliver some of the most toxic venom of all insects as well as a penchant for collecting blue and green turquoise.
These ants will deliberately coat the outside of their domed nests with turquoise, creating what appears to be a roofing veneer. Ant scientists or myrmecologists believe that ants chose turquoise over other colored stones because of its thermal properties. Essentially, turquoise acts as a thermal collector used by ants to maintain a standard temperature year-round in their nests.
In addition, turquoise from caches found in ancient abandoned harvester ant nests have assisted archeologists working at a site near Fajada Butte in Chaco Canyon, N.M., in identifying and dating human activities—like jewelry manufacturing—in the Chacoan Period which lasted from A.D. 900 to early A.D. 1000s.
Ants and people are social creatures; we share a lot in common, including collecting valuable turquoise.
Earth Dr Reese Halter is a broadcaster and biologist. His forthcoming book is entitled “Shepherding the Sea: The Race to Save Our Oceans.”
Text © by Dr Reese Halter 2014. All rights reserved.