FORSTERITE

{{Infobox mineral
| name = Forsterite
| category =
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| image = Forsterite_Stardust.jpg
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| caption = Forsterite (peridot) crystal captured in space by NASA's Stardust spacecraft.
| formula = Magnesium silicate (Mg₂SiO₄)
| molweight =
| color = Green to yellow
| habit =
| system = Orthorhombic
| twinning =
| cleavage = {010}, {100} - imperfect
| fracture = Conchoidal
| mohs = 7
| luster = Vitreous
| refractive = α = 1.635,
β = 1.651,
γ = 1.670
| opticalprop =
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| gravity = 3.222
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'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. It is named after German naturalist Johann Forster.
The gemstone variety of forsterite is known as peridot.
Forsterite reacts with quartz to form the orthopyroxene mineral enstatite in the following reaction:
Mg₂SiO₄ + SiO₂ → 2MgSiO₃.

Contents

See also

References

See also

★ List of minerals

★ List of minerals named after people

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

★ Amethyst Galleries' Mineral Gallery