Turquoise in Matrix
Turquoise (a hydrous phosphate of copper and aluminium) · Semi-Precious Gemstone
Crystal System
Triclinic; typically occurs in massive, cryptocrystalline, or vein-filling habits
Mineral Group
Phosphates (Phosphate group)
Chemical Formula
CuAl6(PO4)4(OH)8·4H2O (often with Fe replacing Al)
Formation Process
Secondary mineral formed by the action of percolating acidic solutions during the weathering and oxidation of pre-existing copper minerals in aluminous rocks
About This Crystal
An opaque, blue-to-green mineral featuring a waxy to sub-vitreous luster. This specific specimen exhibits a heart-shaped cabochon cut with a distinct 'spiderweb' or mottled matrix of brown limonite and green host rock surrounding robin's egg blue turquoise patches.
Physical Characteristics
Color: Sky blue to apple green; Streak: White to greenish-white; Cleavage: None (in massive forms); Fracture: Conchoidal to uneven; Specific Gravity: 2.6–2.9; Fluorescence: Weak greenish-yellow under Longwave UV.
Optical Properties
Refractive Index: 1.610 to 1.650 (often seen as a single spot on a refractometer at 1.61); Birefringence: 0.040 (rarely measurable in massive material); Opaque; No pleochroism in massive form.
Hardness & Durability
Origin Region
Southwestern USA (Arizona, Nevada), Iran (Nishapur), China, and Egypt (Sinai Peninsula)
Hardness & Durability
Mohs Hardness: 5 to 6; Toughness: Fair to Good; Porcelain-like varieties are more durable, while porous chalky varieties are fragile.
Care & Maintenance
Avoid ultrasonic cleaners and steam. Clean with warm, soapy water and a soft brush. Keep away from heat, oils, perfumes, and cosmetics as porosity can cause discoloration.
Rarity & Value
Rarity: Common globally, but 'Sleeping Beauty' blue or fine Persian grades are rare. Value is determined by color intensity, lack of excessive matrix, and hardness. Treatments such as stabilization (resin-impregnation) or dyeing are extremely common.
Special Characteristics
Notable for its 'matrix' (remnants of the host rock) which creates unique patterns; some specimens show a distinct 'color-change' to green as they dehydrate or absorb skin oils over decades.
Lore & History
Used since 5000 BCE in Egypt and by the Aztecs and Native Americans. Historically viewed as a protective stone and a symbol of wealth; traditionally associated with the Throat Chakra and used as a totem for travelers.