Lapis Lazuli
Lapis Lazuli (Rock, primarily composed of Lazurite, Calcite, and Pyrite) · Semi-Precious Gemstone and Decorative Stone
Crystal System
Isometric (Cubic) for individual mineral components; occurs as a compact, massive aggregate
Mineral Group
Silicate group, specifically a feldspathoid
Chemical Formula
(Na,Ca)8(AlSiO4)6(SO4,S,Cl)2 (Lazurite as the primary constituent)
Formation Process
Metamorphic process, specifically contact metamorphism of impure limestone, typically occurring at high temperatures and moderate pressures near igneous intrusions.
About This Crystal
A tumbled, smooth specimen displaying a deep rich royal blue color characteristic of lazurite, mottled with whitish-grey patches of calcite and sparkling golden flecks of pyrite inclusions. It has an opaque transparency and a polished vitreous to greasy luster.
Physical Characteristics
Deep royal blue to ultramarine body color with a light blue to white streak. Cleavage is poor to indistinct. Fracture is uneven to conchoidal. Specific gravity ranges from 2.5 to 3.0. Tenacity is brittle. May show patchy orange to yellow fluorescence under ultraviolet light due to accessory minerals.
Optical Properties
Isotropic (lazurite is typically cubic and singly refractive, though complex microstructures can show anomalous double refraction). Refractive index is approximately 1.50 to 1.67 depending on the aggregate composition.
Hardness & Durability
Origin Region
Badakhshan province in Afghanistan is the classic and most famous source; also found in Russia, Chile, the United States, and Canada. Forms in contact metamorphic limestone (skarns).
Hardness & Durability
Mohs hardness of 5 to 5.5. Moderate toughness, but vulnerable to scratching by harder stones (like quartz) and sensitive to acids, harsh chemicals, and heat.
Care & Maintenance
Clean gently with warm, soapy water and a soft cloth. Avoid ultrasonic cleaners, steam cleaners, prolonged immersion in water, harsh detergents, and acids which can damage the calcite and pyrite components. Store separately to prevent scratching.
Rarity & Value
Uncommon to rare depending on quality. High-value specimens feature deep uniform blue with minimal white calcite and evenly distributed golden pyrite. Widely available in tumbled and carved forms at accessible prices, though top-tier Persian-grade material is expensive. Treatments may include dyeing or waxing to enhance color and luster.
Special Characteristics
Distinctive golden pyrite speckles resembling stars in a night sky and white calcite veining or mottling. Pyrite inclusions are a hallmark of genuine high-quality lapis lazuli.
Lore & History
Used extensively by ancient civilizations including the Egyptians (for burial masks and jewelry), Sumerians, and Mesopotamians. Ground into ultramarine pigment by Renaissance painters. Symbolizes wisdom, truth, and royalty. Associated traditionally with the throat and third-eye chakras in modern crystal healing.