Vanadiocarpholite
Vanadiocarpholite | |
---|---|
General | |
Category | 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 | [2][3] |
Vanadiocarpholite (Mn+2V+3AlSi2O6(OH)4) is straw yellow to brown
orthorhombic crystal system. It is the vanadium rich variety of carpholite
(Mn+2Al2Si2O6(OH)4).
Discovery and occurrence
It was first described in 2005 for an occurrence in the Molinello Mine, Graveglia Valley,
Genova Province, Liguria, Italy.[3] It occurs in chert in a manganese ore deposit as vein fillings in silicified wood.[2]
Chemical composition
It consists of:[2]
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