Azure sky, robin’s egg blue: Vivid shades of turquoise define the color that’s named after this gem.
Turquoise is found in only a few places on earth: dry and barren regions where acidic, copper-rich groundwater seeps downward and reacts with minerals that contain phosphorus and aluminum. The result of this sedimentary process is a porous, semitranslucent to opaque compound of hydrated copper and aluminum phosphate
BIRTHSTONES & ANNIVERSARIES
Turquoise is the traditional birthstone for the month of December and the gem of the 11th anniversary.
Turquoise buried in Ancient Egyptian tombs is among the world’s oldest jewelry.
Ancient Egyptians called turquoise “mefkat,” which also means “joy” and “delight.”
Montezuma, thinking Cortes was Quetzalcoatl, gave him the god’s favorite gem: turquoise.
- Mineral: Turquoise
- Chemistry: CuAl6(PO4)4 (OH)8.5H2O
- Color: Blue to green
- Refractive Index: 1.610 to 1.650
- Birefringence: Not detectable
- Specific Gravity: 2.76 (+0.14, -0.36)
- Mohs Hardness: 5 to 6
Turquoise is judged on its color, texture, and the absence of matrix.
The even blue color of this cabochon would be called Persian blue in the trade.
These free-form turquoise cabochons show a typical matrix pattern.
Although turquoise is usually cut into beads and cabochons, it can also be carved.
Cutters work around large areas of matrix to yield pieces of evenly colored turquoise.