Peridot is the name given to gem quality olivine. It is a magnesium iron silicate and crystallises in the orthorhombic system. Although is hardness is 6.5, its vibrant lime green colour, resulting from a perponderance of magnesium over iron, makes it a sought after gemstone.
Attractive gemstones have been faceted from material found in the Cheviot Hills and Chudleigh Park area, north eastern Queensland. Peridotite bombs from the volcanic areas of western Victoria and northern Tasmania sometimes yield crystals of faceting quality.