Peridot is the gem variety of forsteritic olivine. The green comes from iron. It is orthorhombic and relatively soft for a gem, so jewelry settings should protect the edges.
This page is only for Peridot. Comments below are for this material.
Robert M. Lavinsky, via Wikimedia Commons
Peridot
Specimen Details
- Hardness (Mohs): 6.5–7
- Chemical Formula: (Mg,Fe)2SiO4
- Crystal System: Orthorhombic
- Size: Specimen size varies; record the piece, not the species