Forsterite
From Free net encyclopedia
| Forsterite | |
|---|---|
| Image:PIA02190 Forsterite Stardust.jpg | |
| General | |
| Category | Mineral |
| Chemical formula | Magnesium silicate (Mg2SiO4) |
| Identification | |
| Colour | Green to yellow |
| Crystal system | Orthorhombic |
| Cleavage | {010}, {100} - imperfect |
| Fracture | Conchoidal |
| Mohs Scale hardness | 7 |
| Luster | Vitreous |
| Refractive index | α = 1.635, β = 1.651, γ = 1.670 |
| Specific gravity | 3.222 |
Forsterite (Mg2SiO4) is the magnesium rich end-member of the olivine solid-solution series. Forsterite crystallizes in the orthorhombic system (space group Pbnm) with cell parameters a 4.75 Å, b 10.20 Å and c Å 5.98.
Forsterite is associated with igneous rocks and has also been found in some iron meteorites. In 2005 it was also found in cometary dust returned by the Stardust probe.
The gemstone variety of Forsterite is known as Peridot.
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References
- Deer, W. A., Howie, R. A., and Zussman, J. (1992). An introduction to the rock-forming minerals (2nd ed.). Harlow: Longman ISBN 0-582-30094-0