| Vanadiocarpholite | |
|---|---|
| General | |
| Category | Silicate mineral |
| Formula (repeating unit) | MnVAlSi2O6(OH)4 |
| IMA symbol | Vcar |
| Strunz classification | 9.DB.05 |
| Crystal system | Orthorhombic |
| Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Space group | Ccca |
| Unit cell | a = 13.83 Å, b = 20.681 Å c = 5.188 Å; Z = 8 |
| Identification | |
| Color | Pale-straw yellow, honey-yellow to brown |
| Crystal habit | Prismatic to acicular crystal clusters, vein fillings |
| Cleavage | Perfect on {010} |
| Tenacity | Flexible |
| Luster | Vitreous, silky |
| Diaphaneity | Transparent |
| Optical properties | Biaxial (+) |
| Refractive index | nα=1.684, nβ=1.691, nγ=1.7 |
| Birefringence | 0.0160 |
| References | |
Vanadiocarpholite (MnVAlSi2O6(OH)4) is straw yellow to brown silicate mineral. It crystallizes in the orthorhombic crystal system. It is the vanadium rich variety of carpholite (MnAl2Si2O6(OH)4).
Discovery and occurrence
It was first described in 2005 for an occurrence in the Molinello Mine, Graveglia Valley, Genova Province, Liguria, Italy. It occurs in chert in a manganese ore deposit as vein fillings in silicified wood.
Chemical composition
It consists of:
| Manganese | 15.56% | Mn | 20.09% | MnO |
| Aluminium | 7.64% | Al | 14.44% | Al2O3 |
| Vanadium | 14.43% | V | 21.23% | V2O3 |
| Silicon | 15.91% | Si | 34.04% | SiO2 |
| Hydrogen | 1.14% | H | 10.21% | H2O |
| Oxygen | 45.32% | O |
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.
- ^ Vanadiocarpholite data on Webmineral.com
- ^ Vanadiocarpholite on Mindat.org
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