igneous
Olivine (Peridotite)
Olivine Group; (Mg, Fe)2SiO4
Hardness: 6.5-7 (Mohs scale); Color: Olive-green, lime-green, or brownish-green; Luster: Vitreous (glassy); Crystal Structure: Orthorhombic; Specific Gravity: 3.2-4.4
- Hardness
- 6
- Color
- Olive-green, lime-green, or brownish-green
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Olive-green, lime-green, or brownish-green; Luster: Vitreous (glassy); Crystal Structure: Orthorhombic; Specific Gravity: 3.2-4.4
Formation & geological history
Formed in the Earth's upper mantle and brought to the surface by volcanic eruptions of basaltic lavas or within ultramafic igneous rocks like peridotite or dunite.
Uses & applications
Used as a refractory material in steel making (sand casting), as a gemstone (Peridot) for jewelry, and occasionally as an abrasive or decorative landscaping stone.
Geological facts
Olivine is one of the most common minerals in the Earth's upper mantle. It is also found in meteorites (Pallasites), which can contain beautiful, translucent olivine crystals trapped in a nickel-iron matrix.
Field identification & locations
Identify by its distinctive pistachio to olive-green color and sugary, granular texture in coarse-grained rocks. Common in volcanic regions (Hawaii) or tectonic suture zones. It lacks a clear cleavage, often showing conchoidal fracture.
