Fluellite
Fluellite is a mineral with the chemical formula Al2(PO4)F2(OH)•7H2O. The name is from its chemical composition, being a fluate of alumine (French).[3]
| Fluellite | |
|---|---|
 Fluellite from Leveäniemi Mine, Svappavaara, Kiruna district, Lappland, Sweden | |
| General | |
| Category | Phosphate minerals |
| Formula (repeating unit) | Al2(PO4)F2(OH)•7H2O |
| Strunz classification | 8.DE.10 |
| Crystal system | Orthorhombic |
| Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Space group | Fddd |
| Identification | |
| Color | Colorless, white, pale yellow |
| Crystal habit | Dipyramidal crystals commonly in aggregates; powdery, massive |
| Cleavage | Indistinct on {001} and {111} |
| Mohs scale hardness | 3 |
| Luster | Vitreous |
| Diaphaneity | Transparent |
| Specific gravity | 2.18 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.473 - 1.490 nβ = 1.490 - 1.496 nγ = 1.506 - 1.511 |
| Birefringence | δ = 0.033 |
| Ultraviolet fluorescence | Fluorescent, Long UV=creamy white |
| References | [1][2][3] |
It was first described in 1824 for an occurrence in the Stenna Gwyn Mine, St Stephen-in-Brannel, St Austell District, Cornwall, England.[3]
It is a rare secondary mineral found in complex granite pegmatites where it forms by weathering of earlier phosphate minerals. It is found in association with fluorapatite, wavellite, phosphosiderite, strengite, aldermanite, cacoxenite, variscite, turquoise, fluorite and quartz.[1]
References
- http://rruff.geo.arizona.edu/doclib/hom/fluellite.pdf Handbook of Mineralogy
- http://webmineral.com/data/Fluellite.shtml Webmineral data
- http://www.mindat.org/min-1565.html Mindat.org
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