Olivine has several industrial uses. It is used as a flux for steel production, and is also an important ore of the metal magnesium.
Peridot, the transparent olive-green to yellow-green variety of Olivine, is a well-known gemstone. It is very popular in jewelry, and is used in many jewelry items including rings, bracelets, necklaces, and earrings. Peridot is the birthstone for the month of August.
See more at: http://www.minerals.net/mineral/olivine.aspx