igneous
Olivine (Peridotite)
(Mg,Fe)2SiO4 (Magnesium Iron Silicate)
Hardness: 6.5–7 on Mohs scale; Color: Olive-green, yellow-green; Luster: Vitreous to oily; Crystal structure: Orthorhombic; Specific Gravity: 3.27–4.37; Brittle fracture.
- Hardness
- 6
- Color
- Olive-green, yellow-green
- Luster
- Vitreous to oily
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Physical properties
Hardness: 6.5–7 on Mohs scale; Color: Olive-green, yellow-green; Luster: Vitreous to oily; Crystal structure: Orthorhombic; Specific Gravity: 3.27–4.37; Brittle fracture.
Formation & geological history
Formed deep within the Earth's upper mantle and brought to the surface through volcanic eruptions. It crystallizes from mafic and ultramafic magmas. Found in basaltic lavas and peridotite xenoliths.
Uses & applications
Used as a gemstone (Peridot) for jewelry, as a flux for steel production, as a refractory material for casting molds, and in gem therapy.
Geological facts
Olivine is a primary component of the Earth's upper mantle. It has also been discovered in meteorites (Pallasites) and on the Moon and Mars.
Field identification & locations
Identify by its distinctive olive-green color and sugary, granular texture. Commonly found in basaltic volcanic areas like Hawaii, Arizona, or volcanic regions of Norway and Pakistan.
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