Lapis Lazuli
Lazurite-rich metamorphic rock · Semi-Precious Gemstone / Decorative Stone
Crystal System
Cubic (for Lazurite component); typically occurs in massive, microcrystalline form without visible crystal faces.
Mineral Group
Silicates (Sodalite group) / Tectosilicates
Chemical Formula
(Na,Ca)8(AlSiO4)6(SO4,S,Cl)2 (Lazurite) with Calcite (CaCO3) and Pyrite (FeS2)
Formation Process
Metamorphic; specifically contact metamorphism of limestone or marble where sulfur and sodium are introduced by hydrothermal activity.
About This Crystal
A dense, opaque deep-blue rock. It is a mixture of several minerals: royal blue lazurite (color source), white calcite marbling, and often golden grains of pyrite. The luster is dull to greasy on raw surfaces and vitreous when polished.
Physical Characteristics
Color: Indigo to royal blue with white and grey patches; Streak: Light blue; Cleavage: None (it is a rock); Fracture: Uneven to conchoidal; Specific Gravity: 2.7–2.9; Fluorescence: Calcite patches may glow pink/orange under LWUV.
Optical Properties
Refractive Index: Approx. 1.50 (spot reading); Birefringence: None; Opaque (no pleochroism or dispersion). It is an aggregate, not a single crystal.
Hardness & Durability
Origin Region
Sar-e-Sang, Afghanistan (primary); also Lake Baikal, Russia; the Andes, Chile; and Colorado, USA.
Hardness & Durability
Mohs hardness: 5 to 5.5. Brittle toughness. Sensitive to high heat and pressure due to its composite nature and lack of hardness.
Care & Maintenance
Avoid ultrasonic cleaners and steam. Clean with warm, soapy water only. Sensitive to acids (even lemon juice/vinegar) which can pit the surface. Store away from harder stones like quartz to prevent scratching.
Rarity & Value
Uncommon. Value is determined by the intensity and uniformity of the blue color (the less white calcite, the higher the value) and a balanced sprinkling of pyrite. Treatments: Often dyed to improve blue color or impregnated with wax/resin.
Special Characteristics
Combination mineralogy: The distinctive 'starry night' appearance created by the contrast of golden pyrite against blue lazurite is its most notable feature.
Lore & History
Used for over 6,000 years; highly prized by Ancient Egyptians for amulets (such as the funeral mask of Tutankhamun) and ground up as 'Ultramarine' pigment for Renaissance painters. Traditionally associated with the Throat and Third Eye chakras, symbolizing truth, wisdom, and royalty.