Group: Silicates - nesosilicates
Chemical composition: (Mg,Fe)2SiO4
Colors: Green, yellow, brown, white or black
Hardness: 6.5 to 7
Formation: Orthorhombic crystal; tabular, massive or granular form
Principal Sources: Common in earth's upper mantle and one of the most abundant minerals on the planet.
Special Notes: Peridot is the gem quality variant of olivine. Peridot is one of the few gemstones that occur in only one color, an olive green. The intensity and tint of the green, however, depends on how much iron is contained in the crystal structure, so the color of individual peridot gems can vary from yellow- to olive- to brownish-green. The most valued color is a dark olive-green. Peridot beads were made by Egyptians starting in 1580BC.