Lapis Lazuli
Lapis Lazuli (Rock composed primarily of Lazurite, Calcite, and Pyrite) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Isometric (Lazurite crystals), though usually found in massive, aggregate form
Mineral Group
Silicates (Sodalite group)
Chemical Formula
(Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2 (Lazurite component)
Formation Process
Metamorphic (Contact metamorphism of limestone or marble)
About This Crystal
An opaque, deep royal blue rock with a vitreous to greasy luster. It typically features white veining or mottling from calcite and golden metallic speckles of pyrite. The specimen in the image is a tumbled, polished stone showing characteristic blue saturation and internal fractures.
Physical Characteristics
Color: Deep blue; Streak: Light blue; Cleavage: None; Fracture: Uneven to conchoidal; Specific Gravity: 2.7–2.9; Fluorescence: Often shows patchy orange or pink under LWUV (due to calcite/sodalite).
Optical Properties
Opaque; Refractive Index: Approx. 1.50; No pleochroism or dispersion; Lacks transparency but exhibits a signature 'night sky' appearance due to pyrite inclusions.
Hardness & Durability
Origin Region
Sar-e-Sang, Afghanistan (primary source); also Russia, Chile, and Myanmar
Hardness & Durability
Mohs Hardness: 5.0–5.5; Toughness: Fair to Poor; Sensitive to high pressure and heat.
Care & Maintenance
Clean only with warm, soapy water; avoid ultrasonic or steam cleaners. Highly sensitive to acids (sulfuric acid will release a rotten egg smell). Store separately from harder stones like quartz or sapphire.
Rarity & Value
Common to Uncommon; Value is dictated by the intensity of the blue color and the absence of excessive white calcite. High-grade 'Afghan' blue with minimal pyrite is most valuable. Common treatments include dyeing or resin impregnation.
Special Characteristics
Presence of golden pyrite flecks (often mistaken for gold) and white calcite veins; sulfur within the lazurite lattice is responsible for the intense blue color.
Lore & History
Known since the 7th millennium BC; used in the funeral mask of Tutankhamun and ground into 'ultramarine' pigment for Renaissance paintings. Traditionally associated with the Third Eye chakra, truth, and wisdom.