Lapis Lazuli
Lazurite-bearing metamorphic rock · Semi-Precious Gemstone / Metamorphic Rock
Crystal System
Isometric (Cubic) for primary lazurite crystals; typically occurs in massive, granular, or compact habits as a rock.
Mineral Group
Sodalite group (Silicates); Tectosilicate
Chemical Formula
(Na,Ca)8(AlSiO4)6(SO4,S,Cl,OH)2 (Lazurite component) with Pyrite (FeS2) and Calcite (CaCO3)
Formation Process
Contact Metamorphism; typically forms in crystalline limestones or marbles through the interaction of intrusive igneous bodies with carbonate rocks.
About This Crystal
An opaque metamorphic rock characterized by a deep intense blue color (lazurite), white veins or mottling (calcite), and metallic gold-colored flecks (pyrite). This specimen shows a rough, granular texture with a dull to vitreous luster on fresh surfaces.
Physical Characteristics
Color: Deep blue to violet-blue; Streak: Light blue; Cleavage: None/Indistinct; Fracture: Uneven to granular; Specific Gravity: 2.7 to 2.9; Tenacity: Brittle; Fluorescence: Calcite patches often fluoresce pink/orange under LWUV.
Optical Properties
Refractive Index: Approx. 1.50 (spot Reading); Birefringence: None (isotropic); Optical Phenomena: Metallic luster from pyrite inclusions; no pleochroism due to opacity.
Hardness & Durability
Origin Region
Sar-e-Sang, Badakhshan, Afghanistan (primary); also Lake Baikal, Russia, and the Andes Mountains, Chile.
Hardness & Durability
Mohs Hardness: 5 to 5.5; Fair toughness; Sensitive to high pressure, high heat, and household acids.
Care & Maintenance
Clean only with warm soapy water and a soft cloth; avoid ultrasonic cleaners and steam cleaning. Store away from harder gems like Topaz or Sapphire to avoid scratching.
Rarity & Value
Common to Uncommon; Value is dictated by the depth of blue and the scarcity of white calcite. The 'Royal Blue' Afghan material is most prized. Often dyed to mask white calcite.
Special Characteristics
Presence of Pyrite 'gold' flecks is a diagnostic marker. The blue color is derived from the polysulfide radical (S3-) charge transfer.
Lore & History
Used for over 6,000 years, Lapis was prized in Ancient Egypt for amulets and scarabs, and ground into pigment for ultramarine paint during the Renaissance. Traditionally associated with the Third Eye chakra, symbolizing wisdom and truth.