Turquoise
| Property | Details |
|---|
| Mineral | Turquoise (copper aluminum phosphate) |
| Mohs Hardness | 5 – 6 |
| Refractive Index | 1.610 – 1.650 |
| Birthstone | December (alternative) |
| Major Sources | Iran (Persian), Arizona, Nevada, New Mexico, China |
| Treatments | Stabilization with wax or resin (very common) |
Overview
Turquoise is one of the oldest gemstones in human history, used in jewelry and adornment for over 5,000 years. Its distinctive opaque blue to blue-green color is instantly recognizable and deeply associated with the American Southwest, where it holds spiritual significance in Native American culture.
Varieties & Origins
Persian turquoise from Iran has historically been considered the finest, displaying an even robin's-egg blue without matrix. American turquoise from Arizona (Sleeping Beauty, Kingman, Bisbee), Nevada, and New Mexico is highly valued and comes in a wider range of blues and greens, often with attractive spider-web matrix patterns. Chinese turquoise is the largest commercial source today. The matrix pattern (brown or black veining from surrounding rock) is a matter of personal preference—some prefer clean blue, while others value intricate spider-web patterns.
Quality & Value Factors
The finest turquoise is an even, robin's-egg blue with no matrix. However, attractive spider-web matrix can actually increase the value of certain American turquoise varieties. Hardness varies widely; harder turquoise takes a better polish and is more durable. Most turquoise is stabilized with wax, resin, or polymer to improve durability and color, a common and accepted practice. Untreated, natural turquoise of fine quality commands a significant premium.
Care & Cleaning
Turquoise ranks 5 to 6 on the Mohs scale and is porous. Keep it away from oils, perfumes, chemicals, and prolonged sunlight. Clean with a damp cloth only. Never use ultrasonic cleaners, steam cleaners, or chemical solutions. Turquoise is best suited for earrings, pendants, brooches, and carefully worn rings.