Turquoise
What is Turquoise?
Turquoise is an opaque, blue-to-green mineral that is a hydrated phosphate of copper and aluminum. It’s primarily found in arid regions, including the southwestern United States and northern Mexico. Turquoise has been used for thousands of years and is known for its incredible variety of patterns and colors.
Turquoise is a blue-green mineral known for its unique hue and intricate patterns. Its striking appearance makes it a popular choice for jewelry and decorative items. The stone is often used in necklaces, bracelets, and earrings, and is sometimes used to make beads.
| Chemical Classification | Inorganic - Phosphate |
| Color | Ranges from sky blue to green, depending on its copper and iron content. |
| Streak | White |
| Luster | Waxy to subvitreous. |
| Transparency | Opaque. |
| Occurrence | Iran, United States (especially Arizona and Nevada), Mexico. |
| Formation | Turquoise is typically formed by the leaching of copper in arid regions. |
| Diaphaneity | Opaque |
| Cleavage | Good in one direction |
| Mohs Hardness | 5 to 6. |
| Specific Gravity | Approximately 2.60 to 2.90. |
| Diagnostic Properties | Blue to green color, often with veins. |
| Chemical Composition | CuAl6(PO4)4(OH)8·4H2O |
| Pleochroism | Not exhibited in turquoise. |
| Crystal System | Triclinic |
| Optical Properties | Biaxial (+/-) |
| Refractive Index | 1.610 - 1.650 |
| Birefringence | 0.04 |
| 2V angle | Measured: 68° |
| Dispersion | Not typically relevant for turquoise. |