Olivine (Peridot)

Physical Properties

Hardness: 6.5–7 on the Mohs scale; Color: Olive-green, yellow-green; Luster: Vitreous (glassy); Crystal Structure: Orthorhombic; Cleavage: Poor; Specific Gravity: 3.2–4.3

Formation & Geological History

Formed deep in the upper mantle and brought to the surface by volcanic activity in mafic and ultramafic igneous rocks like basalt or peridotite. Can also be found in certain meteorites.

Uses & Applications

A major component of the Earth's upper mantle; used as a gemstone (Peridot) in jewelry, and industrially as a refractory material in steel making or as a casting sand.

Geological Facts

Olivine is one of the first minerals to crystallize from magma. It is also found on the Moon, Mars, and in the dust of comets.

Field Identification & Locations

Identify by its distinctive olive-green color and glassy appearance. Commonly found in basaltic lava flows and at green sand beaches (like Papakōlea in Hawaii). Collectors should look for transparent, vibrantly colored crystals.

Identified on: 4/22/2026

Mode: Standard