What Is Olivine?
Olivine is a significant rock-forming mineral commonly found in basic and ultrabasic rocks like basalt. It is characterized by its transparent to glassy texture and distinctive yellowish-green to dark-green color. Olivine’s unique color gives it its name, reminiscent of an olive’s green hue.
Olivine’s composition includes four main endmembers: magnesium olivine, iron olivine, manganese olivine (tephroite), and nickel olivine (Liebenbergite). The term “olivine” typically refers to the solid solution series of magnesium and iron olivine. Most olivine’s chemical composition is approximately 70-90% of this solid solution. Its general chemical formula is represented as M2SiO4, where M can be Mg, Fe, Mn, Ni, Ca, and Ti, among others. Olivine’s crystal structure is orthorhombic, based on a silicon Si ion-centered tetrahedron surrounded by four oxygen atoms, with metal elements like magnesium and iron forming nearly octahedral clusters with six oxygen atoms.
The transparent and beautiful crystal variants of olivine, known as peridot, have been highly valued as gemstones since ancient times.
Uses of Olivine
Olivine is not only crucial as a rock-forming mineral in the Earth’s crust but also finds applications as a gemstone due to its striking appearance.
In industrial contexts, olivine sand, derived from crushed and screened olivine, is utilized in various applications. It serves as an industrial material in steel production and fertilizer manufacturing. Furthermore, olivine’s properties of stability, hardness, and high refractory capacity make it suitable for use as a heavy aggregate in concrete and as a construction material for harbors. Its specific gravity is notably higher than that of many other rocks, which is a factor in these applications.