Turquoise
Turquoise · Semi-Precious Gemstone and Decorative Stone
Crystal System
Triclinic, typically massive, microcrystalline, or in veins and nodular crusts rather than well-formed crystals
Mineral Group
Phosphates, specifically a hydrated phosphate of copper and aluminum
Chemical Formula
CuAl6(PO4)4(OH)8·4H2O
Formation Process
Supergene / Hydrothermal secondary process, formed by the action of meteoric waters percolating downward through copper-bearing rocks in arid climates.
About This Crystal
A polished, tumbled specimen displaying a vibrant robin-egg to bright sky-blue color. It features a waxy to sub-vitreous luster with opaque transparency and characteristic dark matrix inclusions or web-like patterns running across the surface.
Physical Characteristics
Color ranges from blue to green-blue with white or dark brown/black matrix veins; streak is white to pale greenish-blue; conchoidal to uneven fracture; specific gravity is approximately 2.60 to 2.90; tenacity is brittle; often exhibits weak green to yellow fluorescence under longwave UV light.
Optical Properties
Biaxial positive with refractive indices around 1.61 to 1.65; birefringence is low (approx. 0.040); generally opaque, meaning optical phenomena like pleochroism are not readily visible.
Hardness & Durability
Origin Region
Notable sources include the Southwestern United States (Arizona, Nevada, New Mexico), Iran (Nishapur), China, and Sinai in Egypt. Forms in arid regions where acidic groundwater reacts with copper and aluminum minerals.
Hardness & Durability
Mohs hardness of 5 to 6; fair to good toughness depending on porosity; sensitive to acids, skin oils, cosmetics, heat, and prolonged direct sunlight which can cause discoloration or dehydration.
Care & Maintenance
Clean gently with warm, soapy water and a soft cloth; avoid ultrasonic cleaners, steam cleaners, harsh chemicals, perfumes, and cosmetics; store separately in a soft pouch away from harder gemstones and direct sunlight.
Rarity & Value
Uncommon to Rare depending on grade, color saturation, and origin (e.g., Persian or high-grade American turquoise is more valuable); frequently stabilized, treated with wax, or dyed to enhance durability and color.
Special Characteristics
Often features intricate spider-web matrix patterns composed of host rock minerals like limonite or sandstone; valued historically for its striking blue color and porous nature that absorbs oils.
Lore & History
Used by ancient civilizations including the Egyptians, Native Americans, and Persians as protective amulets, royal ornaments, and currency. Symbolizes wisdom, protection, and good fortune, commonly associated with the throat chakra in crystal healing traditions.