What is Peridot?
Peridot is the transparent gem variety of olivine, recognised by its fresh yellow-green colour and strong link to mantle rocks and meteorites.
Mineralogy and crystal structure
Reference formula: (Mg,Fe)2SiO4. Peridot is not a separate mineral species: it is gem-quality olivine, usually forsterite-rich. The guide preserves that relationship and uses a representative olivine structure. Peridot is classified with silicates and has a orthorhombic crystal system. Typical hardness is 6.5–7 on the Mohs scale and specific gravity is approximately 3.2–4.4.
Colour, lustre and habit
Typical colours include yellow-green, olive-green, green. The usual granular, prismatic, massive habit and vitreous lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Peridot forms in or is associated with mantle peridotite, basaltic lavas, ultramafic rocks and pallasite meteorites. Important documented localities include Arizona, Pakistan, Myanmar, Egypt, China, Norway and meteorite collections worldwide.
A green gem from the deep Earth
Peridot combines accessible colour with planetary depth. The same olivine family can form in Earth's mantle, erupt in basalt and arrive inside a meteorite.
Collecting and care
Protect from hard impact and acids; store separately from harder gems and disclose treatments or synthetic material when relevant.
