Forsterite
Mineral Mg2SiO4
Also called Chrysolite
About it
The magnesium olivine: glassy olive-green grains in basalt, mantle xenoliths, and marble. Gem peridot comes from San Carlos, Arizona, Zabargad, Egypt, and Pakistan.
- Type
- Mineral
- Group
- Silicate (nesosilicate), olivine group
- Formula
- Mg2SiO4
- Hardness (Mohs)
- 6.5–7
- Specific gravity
- 3.2–3.4
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Orthorhombic
- Colours
- olive green, yellow-green, colourless, white
- Transparency
- transparent, translucent
- Cleavage and fracture
- poor; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.