mineral

Olivine (peridot) grain

Olivine-group silicate, typically forsterite–fayalite solid solution: (Mg,Fe)₂SiO₄

AI-generated identification · may be incorrect

Small translucent yellow-green fragment with vitreous to resinous luster and uneven fracture; likely hardness 6.5–7 Mohs, orthorhombic crystal structure, poor cleavage, and specific gravity about 3.2–4.4. The irregular shape suggests a natural crystal or broken grain rather than a polished gemstone.

Identified September 8, 2026More mineral →

Explore Olivine (peridot) grain in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Olivine crystallizes early from magnesium- and iron-rich mafic or ultramafic magma, commonly in basalt, peridotite, and mantle rocks; Earth examples range from ancient mantle material to geologically young volcanic deposits. The image alone cannot establish its exact locality or age.

Uses & applications

Gem-quality transparent olivine is sold as peridot; ordinary grains are chiefly collector specimens and indicators of mafic/ultramafic rocks, with little industrial use at this size.

Geological facts

Its green color reflects iron and sometimes nickel; iron-rich olivine becomes more yellow-brown. Olivine is a major mineral of Earth’s upper mantle and can weather readily to serpentine and iron oxides.

Field identification & locations

Identify it by its olive-green color, high density, glassy luster, lack of obvious cleavage, and hardness sufficient to scratch window glass; distinguish it from softer green serpentine or glass. Common localities include Hawaii, Arizona, Pakistan, Myanmar, and peridotite/meteorite specimens.