Ashburtonite
| Ashburtonite | |
|---|---|
 | |
| General | |
| Category | Cyclosilicates |
| Formula (repeating unit) | HPb4Cu4Si4O12(HCO3)4(OH)4Cl |
| IMA symbol | Ahb[1] |
| Strunz classification | 9.CF.05 |
| Crystal system | Tetragonal |
| Crystal class | Dipyramidal (4/m) H-M symbol: (4/m) |
| Space group | I4/m |
| Unit cell | a = 14.23, c = 6.1 [Å]; Z = 2 |
| Identification | |
| Color | Blue |
| Crystal habit | Prismatic, needle like in clusters |
| Cleavage | None |
| Fracture | Conchoidal |
| Tenacity | Brittle |
| Luster | Vitreous to adamantine |
| Streak | light blue |
| Diaphaneity | Transparent |
| Specific gravity | Greater than 4.07, calculated 4.69 |
| Optical properties | Uniaxial (+) |
| Refractive index | nω = 1.786 nε = 1.800 |
| Birefringence | 0.0140 |
| References | [2][3][4][5] |
Ashburtonite is a rare lead copper silicate-bicarbonate mineral with formula: HPb4Cu2+4Si4O12(HCO3)4(OH)4Cl.[5]
Geological occurrence[]
Ashburtonite was first described as a secondary mineral in a shear zone in a series of shales and graywackes. It is an alteration product of galena and chalcopyrite.[4] The secondary minerals within the shear consist of carbonates, arsenates, and sulfates of lead and copper, and to a much lesser extent of zinc and iron.[5] Ashburtonite is associated with beudantite, brochantite, caledonite, cerussite, diaboleite, duftite, malachite, plattnerite, adamite, antlerite, bayldonite, bindheimite, carminite, , chlorargyrite, chrysocolla, cinnabar, hemimorphite, hydrozincite, jarosite, lavendulan, linarite, mimetite, olivenite, paratacamite, and rosasite.
Ashburtonite was first described in 1991 for an occurrence in the Anticline prospects 11 km (6.8 mi) southwest of Ashburton Downs in the of Western Australia.[4] It has also been reported from the Tonopah–Belmont Mine in the Big Horn Mountains of Maricopa County, Arizona.[3]
References[]
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Webmineral
- ^ a b Mindat
- ^ a b c Handbook of Mineralogy
- ^ a b c Grice, J. D.; Nickel, E. H.; Gault, R. A. (1991). "Ahsburtonite, a new bicarbonate-silicate mineral from Ashburton Downs, Western Australia: Description and structure determination" (PDF). American Mineralogist. 76: 1701–1707.
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- Tetragonal minerals
- Minerals in space group 87
- Cyclosilicates
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