Lapis Lazuli
Lazurite within a complex rock mixture (Rock consisting mainly of Lazurite, Calcite, and Pyrite) · Semi-Precious Gemstone / Metamorphic Rock
Crystal System
Cubic (Isometric) for individual lazurite crystals; typically occurs in massive, granular, or compact habits as shown in this raw fragment.
Mineral Group
Silicates (Tectosilicates); member of the Sodalite group
Chemical Formula
Na3Ca(Si3Al3)O12S (Lazurite component); contains trace S, Cl, and often associated with FeS2 (Pyrite) and CaCO3 (Calcite)
Formation Process
Metamorphic; typically forms through the contact metamorphism of limestone or marble, where sulfur-rich fluids interact with aluminosilicates.
About This Crystal
An opaque, deep royal blue rock with a dull to vitreous luster on fresh surfaces. This specimen exhibits the characteristic mottled appearance caused by white calcite streaks and potentially golden sparks of pyrite, though the texture here is predominantly rough and earthy.
Physical Characteristics
Color: Azure-blue to violet-blue; Streak: Light blue; Cleavage: Imperfect/None; Fracture: Uneven to conchoidal; Specific Gravity: 2.7–2.9; Fluoresces orange/pink under LWUV due to calcite presence.
Optical Properties
Refractive Index: Approx. 1.50 (variable due to rock composition); Isotropic (Lazurite); Opaque transparency.
Hardness & Durability
Origin Region
Sar-e-Sang, Badakhshan Province, Afghanistan (primary historical source); also Chile, Russia, and Lake Baikal.
Hardness & Durability
Mohs Hardness: 5.5; Brittle toughness; sensitive to pressure and high temperatures. Fair wearability but prone to scratching.
Care & Maintenance
Clean only with warm, soapy water; avoid ultrasonic cleaners, steam, and acidic chemicals (which can dissolve calcite). Store away from harder stones like quartz or corundum.
Rarity & Value
Common to Uncommon; value is highly dependent on the 'Royal Blue' saturation and the absence of visible white calcite; Afghan material is most prized.
Special Characteristics
Displays a distinct 'denim' texture when polished; often contains golden metallic flecks of Pyrite which verify natural origin.
Lore & History
Historically used by Ancient Egyptians for amulets and funeral masks (e.g., King Tutankhamun); ground into 'ultramarine' pigment during the Renaissance. Symbolically associated with truth, wisdom, and the throat chakra.