Olivine

Physical Properties

Hardness: 6.5-7 Mohs; Color: Olive green, dark green, or brownish; Luster: Vitreous (glassy); Crystal structure: Orthorhombic; Cleavage: Poor; Specific gravity: 3.27-4.37.

Formation & Geological History

Formed in igneous environments, primarily as a major component of the Earth's upper mantle and crystallized from mafic and ultramafic magmas. It is commonly found in basalt, gabbro, and peridotite rocks.

Uses & Applications

Used as a gemstone (known as Peridot), in sandblasting processes, as a flux for steel making (to remove impurities), and as a refractory material due to its high melting point.

Geological Facts

Olivine is one of the first minerals to crystallize from a cooling magma according to Bowen's Reaction Series. It has been found in meteorites (Pallasites) and was discovered on Mars by the Mars Exploration Rover.

Field Identification & Locations

Identify in the field by its distinctive olive-green color, glassy luster, and granular habit. It is commonly found in volcanic areas like Hawaii, Arizona, and the Canary Islands.

Identified on: 5/7/2026

Mode: Standard