Peridot is the gem-quality olivine mineral. The mineral, olivine, is a silicate, and its crystal structure is made up of single isolated tetrahedron crystals. This tetrahedron shapehas the same shape as Peridot's hair. Peridot is the birthstone of August, along with Sardonyx.
| Color | Green, Yellow |
| Mohs scale hardness | 7.0 |
| Specific gravity | 3.22 - 3.45 |
| Refractive index | 1.635 - 1.690 |