Glittering Stones >> Semi precious stones >> Olivine

Semi Precious Stone Olivine

The mineral olivine is an orthosilicate of magnesium with the formula (Mg,Fe)2SiO4, in which the ratio of magnesium and iron is found to vary between the 2 end members of forsterite[?] (Mg-rich) and Fayalite [?] (Fe-rich). Olivine crystallizes in the orthorhombic system in somewhat flattened forms but may occur massive or granular. It has a concordat fracture and is rather brittle. The hardness of olivine is 6.5-7, its specific gravity is 3.27-3.37 and it has a vitreous luster. It is usually colored olive-green (hence the name), though it may be reddish from the oxidation of iron. It is transparent to translucent. Olivine occurs in both igneous rocks as a primary mineral and in certain metamorphic rocks, and has also been discovered in meteorites.

Historical Facts of Olivine

Refractive index: 1.630 – 1.650, 1.650 – 1.670, 1.670 – 1.690

Chemical Composition: (Mg, Fe)2SiO4

Mohs Scale Hardness: 6.5 – 7

Density: 3.27 – 3.37

Crystal system: Orthorhombic

Luster: Vitreous

Color: Yellow to yellow-green

Gem Jewelry Olivine