Acuminite
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| Acuminite | |
|---|---|
| General | |
| Category | Halide mineral |
| Formula | SrAlF4OH·(H2O) |
| IMA symbol | Acu[1] |
| Strunz classification | 3.CC.10 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | C2/c |
| Unit cell | a = 13.223, b = 5.175 c = 14.251 [Å]; β = 11.61°; Z = 8 |
| Identification | |
| Color | White |
| Crystal habit | Clusters of acute dipyramidal Spearhead shaped crystals |
| Twinning | Contact on {100} |
| Cleavage | Perfect on {001} |
| Mohs scale hardness | 3.5 |
| Luster | Vitreous |
| Diaphaneity | Transparent |
| Specific gravity | 3.295 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.451 nβ = 1.453 nγ = 1.462 - 1.463 |
| References | [2][3][4] |
Acuminite is a rare halide mineral with chemical formula: SrAlF4(OH)·(H2O). Its name comes from the Latin word acumen, meaning "spear point". Its Mohs scale rating is 3.5.
Acumenite has only been described from its type locality of the cryolite deposit in Ivigtut, Greenland.[2]
See also
[edit | edit source]References
[edit | edit source]
Look up acuminite in Wiktionary, the free dictionary.
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Handbook of Mineralogy
- ^ Mindat.org
- ^ Webmineral data