Lapis Lazuli

Lapis lazuli (a rock primarily composed of Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Rock Type: metamorphic

Lapis Lazuli

Physical Properties

Hardness: 5-5.5 (Mohs scale); Color: Deep blue with gold-flecked pyrite or white calcite streaks; Luster: Vitreous to dull; Crystal structure: Isometric (Lazurite component); Specific gravity: 2.7-2.9

Formation & Geological History

Formed through contact metamorphism where limestone or dolomite is altered by hydrothermal processes. Famous deposits are over 6,000 years old, particularly those in the Sar-e-Sang mines of Afghanistan.

Uses & Applications

Used primarily in jewelry, ornamental carvings, and as a pigment (ultramarine). Historically used for the funeral mask of Tutankhamun and Renaissance paintings.

Geological Facts

The 'gold' specks found in high-quality lapis are actually inclusions of pyrite (fool's gold). It is one of the first gemstones used by human civilizations, dating back to the Neolithic period.

Field Identification & Locations

Identify by its unique 'royal blue' color, often accompanied by gold pyrite specks. Look for it in mountainous regions where limestone has been subject to heat. It is mostly found in Afghanistan, Chile, and Russia.

Identified on: 4/24/2026

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