Lapis Lazuli
Lazurite-rich Metamorphic Rock · Semi-Precious Gemstone / Decorative Stone
Crystal System
Isometric (Lazurite components); generally occurs in massive, granular, or compact forms without visible crystal faces in rock form.
Mineral Group
Silicates (Tectosilicates); member of the Sodalite group.
Chemical Formula
Main constituent Lazurite: (Na,Ca)8(AlSiO4)6(SO4,S,Cl)2 with Pyrite (FeS2) and Calcite (CaCO3)
Formation Process
Metamorphic; specifically contact metamorphism of limestone or marble, forming in skarn deposits through hydrothermal activity.
About This Crystal
An opaque, deep blue rock with a vitreous to greasy luster. It features a mottled appearance due to white veins of Calcite and brassy, metallic flecks of Pyrite. The specimen shown is a tumbled, polished stone with distinct color zoning.
Physical Characteristics
Color: Ultramarine blue with white and gold inclusions; Streak: Light blue; Cleavage: None (poor in individual grains); Fracture: Uneven to conchoidal; Specific Gravity: 2.7–2.9; Fluorescence: Calcite patches may glow pink/orange under LWUV.
Optical Properties
Opaque; Refractive Index: Approx. 1.50 (aggregate); No pleochroism or dispersion; lacks individual optical phenomena like asterism but shows distinct color-blocking.
Hardness & Durability
Origin Region
Sar-e-Sang district in Badakhshan province of Afghanistan (primary source); also Russia (Lake Baikal), Chile (Andes), and Myanmar.
Hardness & Durability
Mohs hardness: 5 to 5.5. Fair toughness; porous and brittle. Sensitive to pressure and high temperatures. Avoid ultrasonic cleaners.
Care & Maintenance
Clean with warm soapy water and a soft cloth only. Highly sensitive to acids (including vinegar) and solvents. Store separately from harder stones like quartz or topaz to prevent scratching.
Rarity & Value
Common to Uncommon; top-tier 'Royal Blue' with minimal calcite is rarer. Value is determined by intense color and balanced pyrite inclusions. Common treatments include dyeing or wax impregnation.
Special Characteristics
Contains metallic golden pyrite 'flecks' which are often used to distinguish it from Sodalite. High calcite content (white streaks) generally lowers the value of the specimen.
Lore & History
Highly prized since antiquity; used in the funeral mask of Tutankhamun and ground into 'ultramarine' pigment for Renaissance paintings. Symbolizes wisdom, truth, and royalty; traditionally associated with the Third Eye chakra.