stishovite
Sign in to savethumb|Pressure-temperature diagram for various forms of silicon dioxide, including stishovite (at top left)
Key facts
- Mineral.mohs
- 9.5
- Mineral.name
- Stishovite
- Mineral.category
- Tectosilicate minerals
- Mineral.group
- Quartz group
- Mineral.image
- stishovite.png
- Mineral.caption
- Crystal structure of stishovite
- Mineral.formula
- SiO2
- Mineral.IMAsymbol
- Sti
- Mineral.strunz
- 4.DA.40 (Oxides)
- Mineral.system
- Tetragonal
- Mineral.class
- Ditetragonal dipyramidal (4/mmm) H–M symbol: (4/m 2/m 2>/m)
- Mineral.symmetry
- P42/mnm (No. 136)
- Mineral.unit cell
- a = 4.1772(7) Å, c = 2.6651(4) Å; Z = 2
- Mineral.color
- Colorless (when pure)
- Mineral.luster
- Vitreous
- Mineral.refractive
- nω = 1.799–1.800 nε = 1.826–1.845
- Mineral.opticalprop
- Uniaxial (+)
- Mineral.birefringence
- δ = 0.027
via Wikipedia infobox
Article
5 sectionsContents
- Appearance
- Synthesis
- See also
- References
- External links
thumb|Pressure-temperature diagram for various forms of silicon dioxide, including stishovite (at top left)
Stishovite ( ) is an extremely hard, dense tetragonal form (polymorph) of silicon dioxide. It is very rare on the Earth's surface; however, it may be a predominant form of silicon dioxide in the Earth, especially in the lower mantle.