Lapis Lazuli

Physical Properties

Hardness: 5-5.5 (Mohs); Color: Deep celestial blue with gold (pyrite) and white (calcite) inclusions; Luster: Vitreous to greasy; Crystal structure: Sodalite group (cubic); Cleavage: Indistinct; Specific gravity: 2.7-2.9

Formation & Geological History

Formed through contact metamorphism where limestone or marble is altered by hydrothermal processes. Major deposits are found in ancient geological structures dating back millions of years, particularly in the Kokcha River valley of Afghanistan.

Uses & Applications

A gemstone primarily used for jewelry, beads, cabochons, and decorative carvings. Historically ground into powder to create the expensive pigment 'ultramarine' used by Renaissance painters.

Geological Facts

Lapis lazuli has been mined for over 6,000 years. It was highly prized by Ancient Egyptians, who used it for the funeral mask of Tutankhamun and believed it represented the night sky.

Field Identification & Locations

Identify in the field by its intense 'royal blue' color, often accompanied by brassy yellow specks of pyrite. It differs from sodalite by its deeper color and presence of pyrite. Major sources include Afghanistan, Chile, and Russia.

Identified on: 4/22/2026

Mode: Standard