Density: 3.3 to 3.5 / Hardness: 8
It is very rare to find well-developed crystals (orthorhombic prism with pyramid), most often they are rounded grains.
Transparent to translucent, green to yellowish-green, vitreous to greasy lustre.
They are found in basalt and ultrabasic rocks. In metamorphic contact rocks (dolomite) and alluvial deposits. But also in some meteorites.
Also known as olivine, peridot, in crystals large enough to be cut, is extremely rare in its deep green and slightly brownish colour.
The island of Zebirget in the Red Sea is home to the most famous peridot deposit. Exploited in antiquity by the Egyptians, it is now exhausted. It was the favorite stone of the pharaohs.