Petalite
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| Petalite | |
|---|---|
| General | |
| Category | Mineral |
| Chemical formula | lithium aluminium tectosilicate mineral LiAlSi4O10 |
| Identification | |
| Color | colorless, grey, yellow, yellow grey, to white |
| Crystal habit | tabular prismatic crystals and columnar masses |
| Crystal system | monoclinic 2/m. |
| Cleavage | Perfect in one plane. |
| Fracture | Subconchoidal |
| Mohs Scale hardness | 6 - 6.5 |
| Luster | Vitreous, pearly on cleavages. |
| Refractive index | nα=1.504 nβ=1.510 nγ=1.516 |
| Pleochroism | - |
| Streak | Colorless |
| Specific gravity | 2.4 |
| Fusibility | 5 |
| Solubility | Insoluble |
| Other | Fluorescent |
Petalite is a lithium aluminiumtectosilicate mineral LiAlSi4O10, crystallizing in the monoclinic system. Petalite is a member of the feldspathoid group. It occurs as colorless, grey, yellow, yellow grey, to white tabular crystals and columnar masses. Occurs in lithium-bearing pegmatites with spodumene, lepidolite, and tourmaline. Petalite is an important ore of lithium. The colorless varieties are often used as gemstones.
Discovered in 1800, type locality: Utö Island, Haninge, Stockholm, Sweden. The name is derived from Greek petalon for leaf.
See also: List of minerals
References
- Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., ISBN 0471805807
- Webmineral (http://webmineral.com/data/Petalite.shtml)
- Mindat (http://www.mindat.org/min-3171.html)
- Neab.net (http://www.geology.neab.net/minerals/petalite.htm)pl:Petalit