Lapis Lazuli

Hardness: 5-5.5 on Mohs scale. Color: Intense azure blue to violet-blue, often with white calcite or pyrite inclusions. Luster: Dull to greasy. Crystal structure: Typically massive, granular, or compact, rarely in dodecahedral crystals. Cleavage: Indistinct. Specific Gravity: 2.7-2.9.

Lapis Lazuli is a metamorphic rock formed by contact metamorphism of limestone with other associated minerals like pyrite, calcite, and diopside. It forms at relatively high temperatures but low to moderate pressures. Its geological age varies depending on the deposit, but many significant deposits are hundreds of millions of years old.

Primarily used as a gemstone in jewelry (cabochons, beads, carvings). Also used for ornamental objects, inlays, and small sculptures. Historically, it was crushed to produce the ultramarine pigment for paints, though now synthetic ultramarine is more common.

Lapis Lazuli has been valued since antiquity for its intense blue color. It was used in ancient Mesopotamia, Egypt, and Rome for jewelry, ornaments, and sculptures. Its pigment, ultramarine, was once more valuable than gold and used by famous Renaissance painters like Michelangelo and Vermeer.

To identify Lapis Lazuli in the field, look for its distinctive deep blue color, often flecked with golden (pyrite) and white (calcite) inclusions. It occurs in crystalline limestone (marble). The most famous and historically significant source is the Sar-e-Sang mine in Afghanistan, which has been mined for over 6,000 years. Other notable occurrences include Russia (Lake Baikal), Chile (Ovalle), and smaller deposits in Canada, Argentina, and the US. Collectors often look for specimens with a vibrant, uniform blue color and appealing distribution of inclusions.