In geology and mineralogy, a mineral group is a set of mineral species with essentially the same crystal structure and composed of chemically similar elements.
For example, the amphibole group consists of 15 or more mineral species, most of them with the general unit formula A
xB
yC
14-3x-2ySi
8O
22(OH)
2, where A is a trivalent cation such as Fe
or Al
, B is a divalent cation such as Fe
, Ca
, or Mg
, and C is an alkali metal cation such as Li
, Na
, or K
. In all these minerals, the anions consist mainly of groups of four SiO
4 tetrahedra connected by shared oxygen corners so as to form a double chain of fused six-member rings. In some of the species, aluminum Al
may replace some silicon atoms Si
in the backbone, with extra B or C cations to balance the charges.
List of groups
- Alunite group
- Amphibole group
- Aragonite group
- Arsenic minerals
- Blodite group
- Calcite group
- Cancrinite group
- Clay minerals group
- Descloizite group
- Dolomite group
- Epidote group
- Feldspar group
- Feldspathoid
- Garnet group
- Hematite group
- Humite group
- Ilmenite group
- Langbeinites
- Mica group
- Pyroxene group
- Rutile group
- Serpentine group
- Smectite group
- Sodalite group
- Spinel group
- Tetradymite group
See also
References
- Stuart J. Mills, Frédéric Hatert, Ernest H. Nickel, and Giovanni Ferraris (2009): "The standardisation of mineral group hierarchies: application to recent nomenclature proposals". European Journal of Mineralogy, volume 21, number 5, pages 1073-1080. doi:10.1127/0935-1221/2009/0021-1994
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