Olivine

A magnesium iron silicate mineral characterized by an olive green color, occurring in igneous and metamorphic rocks. It has two compositional varieties: fayalite (iron rich) and forsterite (magnesium rich). The opaque variety of the stone was found in Egypt, in the lava of Vesuvius, and in the Eifel district of Germany. Transparent, gem quality stones are called peridot, and found in various locations around the world.Olivine beads have been found in pre-Dynastic Egyptian jewelry.