Olivinen

Olivinen is a mineral belonging to the orthorhombic crystal system and is classified as a form of olivine group mineral. Its chemical formula is primarily identified as (Mg, Fe)_2SiO_4, representing a solid solution series between forsterite (magnesium-rich endmember) and fayalite (iron-rich endmember). Olivinen often occurs in mafic and ultramafic igneous rocks, such as basalt, peridotite, and kimberlite.

The mineral exhibits a vitreous to glassy luster and typically appears in pale green to yellow-green hues, although color can vary depending on its iron content. Olivinen crystals are usually small and granular, but larger, well-formed crystals are sometimes found in volcanic rocks and mantle-derived rocks.

Olivinen is notable for its high melting point and significant stability within the Earth's mantle, playing a key role in mantle geology and petrology studies. It is also a valuable indicator mineral for geologists exploring mantle composition and processes.

In terms of physical properties, olivinen has a hardness of 6.5 to 7 on the Mohs scale and a specific gravity ranging between 3.2 and 4.4. It is usually brittle, with a conchoidal fracture, and may be susceptible to secondary alteration, forming serpentine or iddingsite.

Olivinen has industrial applications in refractory materials and as a gemstone when suitably transparent and well-crystallized. Its principal geographical localities include regions in Africa, Asia, Europe, and North America, where it is mined for scientific, industrial, and ornamental purposes.