Cryolite (from other Greek: κρύος - frost + λίθος - stone) is a rare mineral from the class of natural fluorides , sodium hexafluoroaluminate Na 3 [AlF 6 ].
| Cryolite | |
|---|---|
 | |
| Formula | Na 3 [AlF 6 ] |
| Physical properties | |
| Color | Brown Black, Colorless, Gray, White, Russet |
| Trait color | White |
| Shine | Glass, oily |
| Transparency | From transparent to translucent |
| Hardness | 2 - 3 |
| Density | 2.95 - 3.01 g / cm³ |
| Syngonia | Monoclinic (planar) |
Content
- 1 Description
- 2 Origin
- 3 Deposits
- 4 Application
- 5 Artificial production
- 6 notes
- 7 Literature
- 8 References
Description
It crystallizes in monoclinic syngony ; cuboid crystals and twin plates are rare. Usually forms colorless, white or gray crystalline clusters with a glass luster , often contain quartz , siderite , pyrite , galena , chalcopyrite , columbite , cassiterite . Possible coloring by impurities of organic substances [1] .
Origin
It occurs in pegmatites , forming from residual solutions enriched in fluorine .
Deposits
Cryolite deposits are very rare. The largest industrial deposit in Western Greenland ( Ivittuut ), where cryolite forms massive clusters among greisenized granite in the form of a large stock, vertically extending to a depth, was developed until 1987.
Cryolite is found in the Ilmen mountains in the Southern Urals ( Miass ), in Canada and the USA, Colorado .
Application
Cryolite is used in the process of electrolytic production of aluminum , in the production of hydrofluoric acid , glass and enamels . Since the mineral is rare, most of the cryolite used in industry is synthetically produced.
Artificial Reception
Cryolite is artificially produced from fluorite raw materials by the interaction of aluminum fluoride with sodium fluoride , as well as the action of hydrofluoric acid on aluminum hydroxide in the presence of soda .
Notes
- ↑ Sussik-Fornefeld K. Gemstones and Minerals - M.: Astrel, 2001 - p. 288
Literature
- Arkhangelskaya V.V., Getmanskaya T.I., Pechenkin I.G., Shuriga T.N. Cryolite of Russia // Exploration and mineral protection. No. 6. 2010.S. 26-31.