Turquoise
Turquoise · Semi-Precious Gemstone and Decorative Stone
Crystal System
Triclinic, typically massive, microcrystalline, or botryoidal habit; distinct individual crystals are extremely rare.
Mineral Group
Phosphates, specifically a hydrated phosphate of copper and aluminum.
Chemical Formula
CuAl6(PO4)4(OH)8·4H2O
Formation Process
Supergene / Hydrothermal secondary alteration process occurring near the Earth's surface in arid climates, where circulating meteoric waters leach copper and phosphorus from surrounding rocks and precipitate turquoise in veins and cavities.
About This Crystal
An opaque specimen displaying a vibrant robin's egg blue to greenish-blue coloration with characteristic dark, web-like matrix veins (limonite or sandstone inclusions). It has a waxy to sub-vitreous luster on polished areas and an irregular, compact structure typical of tumbled or nodular turquoise.
Physical Characteristics
Color ranges from sky blue to blue-green; streak is white to pale greenish-blue. Cleavage is perfect in two directions but rarely seen due to massive habit. Fracture is conchoidal to uneven. Specific gravity ranges from 2.60 to 2.89. Tenacity is brittle. May show weak pale green or yellow-green fluorescence under shortwave UV light.
Optical Properties
Biaxial (+) with refractive indices typically around 1.61 to 1.65. It is doubly refractive but rarely exhibits distinct optical phenomena beyond its characteristic color and matrix web patterns.
Hardness & Durability
Origin Region
Notable sources include the southwestern United States (Arizona, Nevada, New Mexico), Iran (Nishapur), China, and the Sinai Peninsula in Egypt. It forms in arid regions where acidic groundwater reacts with copper-bearing minerals and aluminum-rich rocks.
Hardness & Durability
Mohs hardness of 5 to 6, making it relatively soft and sensitive to scratching. Toughness is fair to poor depending on porosity. It is sensitive to oils, cosmetics, acids, and high heat, which can alter its color.
Care & Maintenance
Clean gently with warm, soapy water and a soft cloth; avoid ultrasonic cleaners, steam, harsh chemicals, perfumes, and prolonged exposure to direct sunlight or body oils to prevent discoloration and dehydration.
Rarity & Value
Uncommon to Rare depending on grade and origin. High-grade natural turquoise with spiderweb matrix is highly valued and expensive, whereas treated, stabilized, or reconstituted turquoise is common and affordable. Treatments such as stabilization (resin impregnation) are extremely common.
Special Characteristics
The prominent dark spiderweb matrix formed by host rock inclusions (such as iron oxides or limonite) gives distinct aesthetic appeal and helps identify natural matrix patterns.
Lore & History
Used for millennia by ancient Egyptians, Native Americans, and Persians as a protective amulet, talisman of power, and symbol of wealth and health. In modern crystal healing, it is associated with the throat chakra, communication, emotional balance, and spiritual grounding, though these are traditional beliefs rather than scientific claims.