ALL ABOUT TURQUOISE GEMSTONES
What does Turquoise Mean?
The word Turquoise is an Old French word meaning “Turkish” which is where the Europeans first found the gem mined from the Khorasan Province in Iran for sale in the bazaars of Turkey. Although Turquoise is the word we’ve used for several centuries, Pliny the Elder called it Callais, the miners in Iran searched for Priouzeh, and the Aztecs carved their power statues of Moctezuma from Teoxihuitl.
The Colors of Turquoise
The most prized color of Turquoise in antiquity, and now, is the intense blue most commonly associated with Turquoise as a color, but is very hard to find naturally in a stone. In ancient times, the best mines producing the finest colors of turquoise were found in Persia, but in the late 1800s, miners re-discovered Aztec mines in Arizona and the Western United States. The turquoise from these mines rivaled any found in Persia and exceeded the quality in many cases. Today the United States has become the largest producer of gem-quality turquoise with the finest specimens being from Arizona, and Nevada. The color of the stone comes from copper, and varies depending on the concentration of copper in the chemical formula. Turquoise that is greener in color has a higher concentration of iron.
Turquoise Facts
Chemically Turquoise is made of Copper, Aluminum and trace amounts of Iron in what is called a “hydrous phosphate”; its chemical formula is Cu(Al,Fe3+)6(PO4)4(OH)8 x4H2O. Turquoise is a very soft stone ranging from 0 – 6 on the Mohs’ scale with most of the stones falling in the 5-6 range, or about as hard as the glass in your windows. It has a perfect cleavage and conchoidal fracture with crystals being rare to form in the stone.
How Turquoise Forms
Turquoise forms as a secondary mineral by percolation through acidic aqueous solutions where the primary rock is volcanic with high levels of limonite, iron oxide and copper. In other words; water, which has been heated under the earth, rises upward through limonite rock and creates turquoise in the cracks and crevasses of weathered rock. This occurs in arid regions like the American Southwest and the Middle East. As a side note: Turquoise is mined in Arizona, New Mexico, Colorado, Nevada, and California…all over the southwestern US except Utah, which is known for our copper mine! That’s okay, though, we have Variscite – and we’ll talk about that a little later.