Pollucite
| Pollucite | |
|---|---|
 |
|
| General and classification | |
| chemical formula | (Cs, Na) 2 Al 2 Si 4 O 12 • H 2 O |
|
Mineral class (and possibly department) |
Silicates and Germanates |
|
System no. to Strunz and to Dana |
9.GB.05 ( 8th edition : VIII / J.27) 77.01.01.02 |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | m 3 m |
| Space group | Ia 3 d |
| Lattice parameters | a = 13.67 Å Please complete the source as an individual reference |
| Formula units | Z = 16 Please complete the source as an individual reference |
| Physical Properties | |
| Mohs hardness | 6.5 |
| Density (g / cm 3 ) | 2.9 |
| Cleavage | is missing |
| Break ; Tenacity | shell-like to uneven |
| colour | colorless, white, gray, pale pink, blue |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss, matt |
Pollucite is a rare mineral from the mineral class of silicates and germanates . It crystallizes in the cubic crystal system with the composition (Cs, Na) 2 Al 2 Si 4 O 12 • H 2 O and rarely forms cubic, dodecahedral or trapezoidal crystals up to 12 cm in size, but mostly rounded, massive grains and is colorless, white or gray, sometimes pink, purple or blue colored.
Pollucite and analcime form a series of minerals.
Etymology and history
Pollucite was first found in 1846 by August Breithaupt in the type locality San Piero in Campo on the Italian island of Elba . He named the mineral after the Greek mythical figure Pollux first Pollux , later the name was changed to pollucite. The reason for choosing this name is that the mineral is always associated with petalite , which he accordingly called castor . The mineral was also chemically examined by CF Plattner, but since the contained element cesium was not yet known, he erroneously determined the mineral as containing a lot of potassium .
classification
In the scheme according to Strunz the mineral is to the zeolite , a subset of the scaffolding or tectosilicates counted. In the 8th edition , it forms a group of cube zeolites with analcime , faujasite (Ca) , faujasite (Mg) , faujasite (Na) , paulingite (Ca) , paulingite (K) and wairakite . In the 9th edition it forms with ammonioleucite , analcime, hsianghualite , leucite , lithosite and wairakite a subgroup of the chain silicates with simply connected rings of four.
In the Dana system, pollucite belongs to the zeolite group of tectosilicates and forms a group with analcime, hsianghualite, laumontite and wairakite.
Education and Locations
Pollucite is found in lithium-rich granite pegmatites . It is associated with quartz , spodumene , petalite, amblygonite , lepidolite , elbaite , cassiterite , columbite , apatite , eucryptite , muscovite , potassium feldspar , albite and microcline .
The largest pollucite finds are known from Lac du Bonnet in the Canadian province of Manitoba . Other important sites are Elba, Bikita in Zimbabwe , Karibib in Namibia , Afghanistan , Pakistan , Skellefteå in Sweden , Itinga in Brazil and the US states of Maine , Connecticut , South Dakota and California .
Crystal structure
Pollucite crystallizes in the cubic crystal system in the space group with the lattice parameter a = 13.67 Å , and 16 formula units per unit cell .
use
The pollucite deposits in Lac du Bonnet are the raw material for the extraction of all cesium compounds and also of elemental cesium.
See also
Individual evidence
- ↑ August Breithaupt: New Minerals, 4th and 5th Kastor and Pollux . In: Annalen der Physik und Chemie , 1846, 69, pp. 436-439.
- ↑ CF Plattner: Chemical investigation of two new minerals from the island of Elba, determined mineralogically by Prof. Breithaupt . In: Annalen der Physik und Chemie , 1846, 69, pp. 443-447.
- ^ List of minerals according to Dana at webmineral.com.
- ↑ Manfred Bick, Horst Prinz: Cesium and Cesium Compounds . In: Ullmann's Encyclopedia of Industrial Chemistry , Wiley-VCH, Weinheim 2005 ( doi : 10.1002 / 14356007.a06_153 ).
literature
- Pollucit in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf )
