Turquoise

Turquoise is an opaque blue-to-green gemstone classified as a hydrous phosphate of copper and aluminum, with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. The stone forms in arid regions where acidic, copper-rich groundwater percolates through aluminum-bearing rock over millions of years. Its color ranges from sky blue and robin's-egg blue through blue-green to apple green, with the hue determined by copper (blue) and iron (green) content. Many specimens show a matrix of host rock in brown, black, or tan webbing.

Where Turquoise Comes From

The oldest known Turquoise mines operated on the Sinai Peninsula around 3000 BC, worked by Egyptian laborers for pharaohs of the First Dynasty. Persian (Iranian) deposits near Nishapur have produced the pure sky-blue material prized for over 2,000 years, and the term "Persian blue" still describes the highest-grade matrix-free stones. Chinese Turquoise has been mined in Hubei Province for centuries.

The American Southwest is the largest modern source. Arizona, Nevada, and New Mexico host commercial mines including Sleeping Beauty (Arizona), Kingman (Arizona), Royston (Nevada), and Number 8 (Nevada). Sleeping Beauty closed to Turquoise extraction in 2012, which pushed prices for that material sharply upward. Mexico, Chile, and Australia also produce smaller quantities.

Properties and How to Identify Turquoise

Turquoise registers 5 to 6 on the Mohs hardness scale, softer than quartz and prone to scratching. It has a specific gravity of 2.6 to 2.9 and is almost always opaque, though rare translucent crystals have been documented from Virginia's Bishop Mine. The stone can be confused with chrysocolla, variscite, and dyed howlite. A reliable test is hardness combined with the response to heat: Turquoise may discolor or crack when exposed to high temperatures, while plastic imitations melt.

Most Turquoise on the market is treated. Stabilization with clear epoxy resin hardens porous material and locks in color — this is industry-standard for about 90% of stones sold. Waxing and oiling are older methods still used on higher grades. Reconstituted Turquoise (ground powder bonded with resin) and dyed material are also common. Natural, untreated Turquoise from mines like Lander Blue or Bisbee commands premium prices. We label stabilized stones as such.

Turquoise in Sterling Silver Jewelry

Cabochon is the dominant cut for Turquoise because it showcases color saturation and matrix patterns while protecting the relatively soft surface. Inlay work, freeform slabs, and rough nugget beads are also standard in Southwestern silversmithing. Sterling silver (.925) has been paired with Turquoise by Navajo, Zuni, and Hopi artisans since the 1870s; the cool white metal sharpens the blue and the slight oxidation in bezel settings adds contrast. At SilverRush Style, our turquoise jewelry typically runs $25 to $180 depending on stone size, grade, and setting complexity.

Caring for Turquoise

Clean Turquoise with a soft cloth and, if needed, lukewarm water with mild soap applied briefly. Never use ultrasonic cleaners, steamers, or chemical jewelry dips — the stone is porous and will absorb solvents, oils, cosmetics, and perspiration, which can shift its color from blue toward green over time. Remove Turquoise jewelry before swimming, showering, applying lotion, or cleaning. Store pieces separately in a soft pouch, away from direct sunlight and heat sources that can dehydrate the stone and cause crazing.

Frequently Asked Questions