Turquoise can be sky blue to apple green and any shade of blue, green or teal in between. Being a fairly soft stone (5.5-6.5 on the mohs scale), turquoise often is not suitable for cutting into stones and beads used for jewelry applications and that is why 95% of the turquoise for sale on the market today has been "stabilized" (a process using pressure and heat to fill the microscopic gaps in the stone with plastic resin, thus making the stone hard enough to cut and polish). The mineral turquoise is formed by a chemical reaction which occurs when water containing specific minerals such as copper and aluminum leak through a rock. Varying amounts of Copper and iron change the color shades. The copper is what gives the mineral its blue coloring and high iron levels mean greens and yellows predominate. Most of the time, turquoise occurs as vein or seam fillings, and as compact nuggets; that are mostly small in size. Different mines are known for their color shades, but no matter what country, turquoise is comprised of the same minerals and the beauty transcends the boundaries of location. Some turquoise contains inclusions of its host rock (known as matrix) that appear as black or brown spider-webbing or patches within the material.
Turquoise is often recovered as a byproduct of large-scale copper mining operations and throughout history, deposits of turquoise have been found in the following countries; Afghanistan, Africa, Armenia, Australia, Brazil, Chile, China, Egypt, Iran (Persia), Israel, Mexico, Russia, Siberia, Tibetan, Turkey and the United States. Currently it is mostly mined in the China, Iran, Mexico, Tibet and the United States.
Large mines were reported around 3,200 BC in the Sinai. The oldest known source of Chinese turquoise is the Maghara Wadi mines in the Sinai Peninsula. China has been a minor source of turquoise for more than 3,000 years and even today turquoise is being mined there. These deposits found have been found in Anhui, Maanshan, Sichuan, Yunxian, Zhushan and Hubei province. Currently producing mines include the Anhui turquoise mine has just recently been opened and produces natural high blues. Located in a remote area of northwest of East China, along Yangtze River Basin, the material is difficult to obtain being deep under the ground, 100 meters, in which the miners have to drill deep holes to obtain the material and hand carry it out of the region. Hubei Chinese turquoise is mined in the north west of Hubei province near to Wudangshan (Wudang Mountain). This small surface deposit of turquoise was discovered while looking for Iron ore and is very beautiful color shades due to the high iron content present.
Mexico turquoise is currently fairly available on the market with several recent mines re-opening. Most of Mexico's turquoise comes from Sonora directly below the Arizona border. Campitos turquoise comes from the Pino Chueco mine in Sonora, Mexico which has produced turquoise, since the mid-1980s that is medium light-blue with no matrix and some pyrite. Campitos turquoise is very unique in that it is found as free-form nuggets in clay material, rather than in rock veins. Also in Sonora, the Campo Frio mine produces greenish stone sometimes with spiderweb and often pyrite in the matrixing. The Nacosari turquoise mine is located in north western Mexico, in a large open pit copper mine is producing clear bright blue turuqoise. Because of an unstable political situation in this region, the mine and local government has stopped mining of the rough, and if caught with the rough it is confiscated.
In the US, deposits of turquoise have been found in the following states; Arizona, California, Colorado, Montana, New Mexico, Nevada, Utah and Virginia. Only a small percentage of them are still producing with the majority being depleted or closed down.
See turquoise collection HERE