igneous
Olivine (Peridotite/Dunite)
Olivine (Mg,Fe)2SiO4 within Peridotite
Hardness: 6.5–7; Color: Olive green to yellowish-green; Luster: Vitreous to greasy; Crystal Structure: Orthorhombic; Cleavage: Poor; Specific Gravity: 3.2–4.4
- Hardness
- 6
- Color
- Olive green to yellowish-green
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 6.5–7; Color: Olive green to yellowish-green; Luster: Vitreous to greasy; Crystal Structure: Orthorhombic; Cleavage: Poor; Specific Gravity: 3.2–4.4
Formation & geological history
Formed in the Earth's upper mantle through crystallization of magma at high temperatures. Often brought to the surface by volcanic activity or tectonic uplifting as xenoliths. Most specimens date back to the Precambrian or Paleozoic eras.
Uses & applications
Industrial use as a flux for steelmaking, refractory sand for casting, and gem-quality specimens (Peridot) are used in jewelry. Also used for CO2 sequestration research.
Geological facts
Olivine is one of the most common minerals in the Earth's interior and is a primary component of the mantle. It has also been discovered in lunar rocks and meteorites, specifically Pallasites.
Field identification & locations
Identify by its distinct olive-green color and sugary (granular) texture. Commonly found in basaltic lava flows and deep-seated intrusive rocks like gabbro. Collectors find specimens in volcanic regions such as Arizona, Hawaii, and Norway.
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