Lapis Lazuli
Lapis Lazuli (Rock, not a mineral; primary mineral Lazurite) · Decorative Stone / Semi-Precious Gemstone
Crystal System
Cubic (Isometric) for lazurite component
Mineral Group
Silicates (specifically Feldspathoid group)
Chemical Formula
(Na,Ca)8Al6Si6O24(S,SO4)1-x
Formation Process
Metamorphic, formed by contact metamorphism of limestone into skarn
About This Crystal
Deep blue opaque polished bead set in jewelry, displaying characteristic golden pyrite flecks and white calcite veins.
Physical Characteristics
Color ranges from deep royal blue to ultramarine; streak is light blue; cleavage is none; fracture is uneven to conchoidal; specific gravity is 2.7 to 2.9; brittle tenacity; typically no significant fluorescence.
Optical Properties
Refractive index is approximately 1.50; aggregate nature; doubly refractive in individual microcrystals; no pleochroism.
Hardness & Durability
Origin Region
Afghanistan, Chile, Russia, USA
Hardness & Durability
Mohs hardness of 5 to 5.5; fair to poor toughness; sensitive to acids, harsh chemicals, and high heat; moderate wearability for jewelry requiring careful handling.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid ultrasonic cleaners, steam, and harsh chemicals; store separately to prevent scratching.
Rarity & Value
Uncommon to Rare depending on grade; valued for deep uniform blue color and minimal white calcite with well-distributed pyrite; treated often by stabilization or dyeing for lower grades.
Special Characteristics
Inclusions of golden pyrite crystals creating a night-sky appearance; occasional white calcite mottling.
Lore & History
Historically used in ancient Egypt for amulets and scarabs, and ground into ultramarine pigment by Renaissance artists. Associated with truth, wisdom, and the third-eye chakra in metaphysical traditions.