Turquoise
Turquoise · Semi-Precious Gemstone and Mineral Specimen
Crystal System
Triclinic, typically occurs in massive, microcrystalline, or botryoidal habits rather than distinct individual crystals
Mineral Group
Phosphates, specific subgroup is hydrated copper and aluminum phosphates
Chemical Formula
CuAl6(PO4)4(OH)8·4H2O
Formation Process
Supergene/Hydrothermal, formed by the action of descending meteoric waters percolating through copper-bearing aluminum rocks in arid climates
About This Crystal
An opaque, bright blue to blue-green tumbled or natural nugget with dark brown to black web-like matrix inclusions running through it, exhibiting a waxy to sub-vitreous luster
Physical Characteristics
Color ranges from robin's egg blue to greenish-blue with a white or pale greenish-blue streak, conchoidal to uneven fracture, poor cleavage in two directions, specific gravity around 2.60-2.90, brittle tenacity, and weak green or yellow fluorescence under longwave UV light
Optical Properties
Biaxial positive with refractive indices around 1.61 to 1.65, generally opaque so optical phenomena like pleochroism are not typically observed, exhibits a waxy luster
Hardness & Durability
Origin Region
Notable sources include the southwestern United States (Arizona, Nevada, New Mexico), Iran (Nishapur), China, and Egypt (Sinai Peninsula)
Hardness & Durability
Mohs hardness of 5 to 6, fair to good toughness but somewhat porous, sensitive to chemicals, cosmetics, oils, and high heat which can alter its color
Care & Maintenance
Clean gently with warm soapy water and a soft cloth, avoid ultrasonic and steam cleaners, harsh chemicals, acids, perfumes, and prolonged exposure to direct sunlight or body oils
Rarity & Value
Uncommon to Rare depending on grade and origin, value is determined by intense robin's egg blue color, minimal matrix or attractive spiderweb patterns, and absence of extensive stabilization treatments; prices range from accessible for stabilized stones to high for natural, high-grade collector pieces
Special Characteristics
Often features spiderweb matrix formed by host rock inclusions like limonite or sandstone, highly porous nature leading to widespread stabilization treatments
Lore & History
Historically revered by ancient civilizations including the Egyptians, Native Americans, and Persians as a protective amulet, symbol of wealth, and stone of healing, associated traditionally with the throat chakra to enhance communication and spiritual grounding