Lapis Lazuli
Lazurite-rich rock (Lapis Lazuli) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Triclinic/Isometric (as an aggregate rock); Lazurite crystals are Isometric (dodecahedral habits)
Mineral Group
Silicates (Sodalite group); specifically a Tectosilicate rock
Chemical Formula
(Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2 (Lazurite) with inclusions of Pyrite (FeS2) and Calcite (CaCO3)
Formation Process
Metamorphic; typically forms through contact metamorphism of limestones often associated with hydrothermal activity
About This Crystal
An opaque, deep blue rock consisting of a mixture of minerals. Exhibits a vitreous to greasy luster, often containing gold-colored flecks of pyrite and white streaks of calcite.
Physical Characteristics
Color: Ultramarine to deep blue; Streak: Light blue; Cleavage: None (non-existent in rock form); Fracture: Uneven/Conchoidal; Specific Gravity: 2.7-2.9; Fluorescence: Often inert, but calcite veins may fluoresce pink/orange.
Optical Properties
Opaque; Refractive Index: Approx. 1.50; No pleochroism or birefringence visible due to opacity.
Hardness & Durability
Origin Region
Sar-e-Sang, Afghanistan (most famous); Chile, Russia, Myanmar, and the USA
Hardness & Durability
Mohs hardness: 5 to 5.5; Fair toughness; sensitive to pressure and high temperatures. Moderate wearability in jewelry.
Care & Maintenance
Avoid ultrasonic/steam cleaners; clean with warm soapy water only. Susceptible to acids and household chemicals. Keep away from prolonged sunlight to prevent fading of dyed specimens.
Rarity & Value
Rarity: Common (commercial grade) to Rare (gem-quality Afghan material). Value determined by intense blue saturation and lack of visible calcite. Common treatments include dyeing and resin impregnation.
Special Characteristics
Golden pyrite inclusions (fools gold), color-zoning, and a distinctive 'denim' look in lower-grade specimens.
Lore & History
Used since the 7th millennium BC; prized by Egyptians for amulets and funeral masks (King Tutankhamun). Historically ground into 'ultramarine' pigment for Renaissance painters. Traditionally associated with the Third Eye/Throat chakras and wisdom.