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Olivine is usually colored olive-green (hence the name), though it may be reddish from the oxidation of iron. It has a conchoidal fracture and is rather brittle. The hardness of olivine is 6.5-7, its relative density is 3.27-3.37 and it has a vitreous lustre. It is transparent to translucent.
Transparent olivine is sometimes used as a gemstone, often called peridot, the French word for olivine. It is also called chrysolite from the Greek words for gold and stone.
Olivine forms from magmaThis article is about the type of rock. For magmas in mathematics, see Magma (algebra). For the experimental jazz band, see Magma (band). For the computer algebra system, see Magma computer algebra system. For the EDA software company, see Magma Design Au that is rich in magnesium and low in silica, forming such rocks as gabbroGabbro is a dark, coarse-grained, intrusive igneous rock chemically equivalent to basalt. It is a plutonic rock, formed when molten magma is trapped beneath the Earth's surface and cools slowly into a hard, coarsely crystalline mass. It is dense, greenish, peridotitePeridotite is a dense, coarse grained ultrabasic rock, consisting mainly of the minerals olivine and pyroxene. Peridotite is also a group of mantle derived igneous rocks. They all are ultramfic or ultrabasic meaning the contain less than 45% silica and ar and basaltBasalt is an extrusive igneous rock, sometimes porphyritic, and is often both fine-grained and dense. Basalt in the tops of subaerial lava flows and cinders will often be highly vesiculated, imparting a lightweight "frothy" texture to the rock. The term b. The metamorphosis of impure dolomiteFor the European mountain range, see Dolomites Dolomite is a mineral (formula CaMg(CO)) consisting of a calcium magnesium carbonate found in crystals and in beds as dolostone. A pure form of dolostone would be rare, however; it usually intergrades with li or other sedimentary rockshale overlaid by limestone. Cumberland Plateau, Tennessee. Sedimentary rock is one of the three main rock groups (along with igneous and metamorphic rocks) and is formed in three main ways—by the deposition of the weathered remains of other rocks (known with high magnesium and low silica content also seems to produce Mg-rich olivine, or forsterite. It also forms over 50% of the Earth's upper mantle making it one of the Earth's most common minerals by volume. Olivine has also been discovered in meteorites as well as on Mars and on the moon.