igneous
Olivine (in Peridotite/Dunite form)
Magnesium Iron Silicate (Mg,Fe)2SiO4
Hardness: 6.5–7 (Mohs scale); Color: Olive-green, yellowish-green; Luster: Vitreous (glassy); Crystal Structure: Orthorhombic; Specific Gravity: 3.27–4.37.
- Hardness
- 6
- Color
- Olive-green, yellowish-green
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 6.5–7 (Mohs scale); Color: Olive-green, yellowish-green; Luster: Vitreous (glassy); Crystal Structure: Orthorhombic; Specific Gravity: 3.27–4.37.
Formation & geological history
Formed deep within the Earth's mantle and brought to the surface by tectonic activity or volcanic eruptions. It crystallizes from magma at very high temperatures. Predominantly found in ultramafic rocks of various geological ages.
Uses & applications
Used as a flux in steel making, as a refractory material in various industrial furnaces, and for sandblasting. High-quality transparent specimens (Peridot) are used in jewelry.
Geological facts
Olivine is the primary component of the Earth's upper mantle. It has also been discovered in meteorites and on the surfaces of Mars and the Moon.
Field identification & locations
Identify by its distinctive olive-green color and sugary (granular) texture. Commonly found in basaltic lava flows and ophiolite complexes. Collectors look for vibrant color and lack of dark inclusions.
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