Olivine
Image: <a href="//commons.wikimedia.org/wiki/User:Islam90" title="User:Islam90">Islam90</a> (CC BY-SA 4.0)
Mineral NameOlivine
Chemical Formula(Mg,Fe)2SiO4
Mohs Hardness6.5
Crystal Systemorthorhombic
Lustervitreous
Streak Colorwhite
Cleavagepoor/indistinct on {010} and {100}
Fractureconchoidal
Specific Gravity3.27
Colorsgreen, yellowish-green, olive-green, brownish-green
Transparencytransparent
Type LocalitySan Carlos Apache Reservation (Arizona, USA), St. John's Island (Egypt), Norway, Hawaii (USA)
Mineral GroupSilicates (Nesosilicates)
Usesjewelry (as peridot), refractory material, industrial (magnesium source), collector
Associated Mineralspyroxene, plagioclase, chromite, magnetite, serpentine
Raritycommon
Description
The image shows a microscopic view of olivine grains in cross-polarized light, displaying vibrant interference colors ranging from yellow, orange, and red to blue and purple, characteristic of its high birefringence. The grains exhibit an anhedral to subhedral granular texture, with some showing fracturing.
Geological Context
Olivine is a primary mineral in mafic and ultramafic igneous rocks such as basalt, gabbro, peridotite, and dunite, crystallizing at high temperatures from magnesium-rich magmas. It is also found in some metamorphic rocks and is a significant component of the Earth's upper mantle, as well as in meteorites.
