Olivine

Olivine is a common green rock-forming silicate mineral. Olivine is also called chrysolite or Peridote, the August birthstone. Olivine is the most common mineral in the silicate group. Olivine is named for its olive-like color, which it gets from magnesium and Iron, although it can turn reddish. Olivine has also been in metorites, comets, Moon surface, and Mars surface. Olivine weathering often happens on the earth's surface. Aluminum workers use olivine sand in their products. Olivine sand is a kind of dark sand.

Properties of olivine
Olivine is translucent to transparent and has a vitreous luster. There is a colorless streak. Kinds of olivine are almost always green. Olivine has an orthorhomic crystal structure. Olivines specific gravity is 3.3.