Epidote group
Sorosilicate mineral
From Wikipedia, the free encyclopedia
Epidotes are a group of sorosilicate minerals that are common in igneous and metamorphic rocks.[1][2][3]
CategorySorosilicates
Formula(A2+1A2+2)(M3+1M3+2M3+3)O[Si2O7][SiO4](OH)
| Epidote group | |
|---|---|
| |
| General | |
| Category | Sorosilicates |
| Formula | (A2+1A2+2)(M3+1M3+2M3+3)O[Si2O7][SiO4](OH) |
| IMA symbol | Ep |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H–M symbol) |
| Space group | P21/m |
| Identification | |
| Color | Yellow-green, pistachio green, greenish black, brownish-green, green, black |
| Crystal habit | Prismatic, fibrous, druse/encrustation, massive |
| Twinning | On [100] |
| Cleavage | {001} perfect and {100} imperfect |
| Mohs scale hardness | 6–7 |
| Luster | Vitreous |
Epidote member species
- Clinozoisite, (CaCa)(AlAlAl)O[Si2O7][SiO4](OH)
- Epidote, (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH)
- Epidote-(Sr), (CaSr)(AlAlFe3+)O[Si2O7][SiO4](OH)
- Hancockite, (CaPb)(AlAlFe3+)O[Si2O7][SiO4](OH)
- Heflikite, (CaCa)(AlAlSc)O[Si2O7][SiO4](OH)
- Mukhinite, (CaCa)(AlAlV3+)O[Si2O7][SiO4](OH)
- Niigataite, (CaSr)(AlAlAl)O[Si2O7][SiO4](OH)
- Piemontite, (CaCa)(AlAlMn3+)O[Si2O7][SiO4](OH)
- Piemontite-(Pb), (CaPb)(AlAlMn3+)O[Si2O7][SiO4](OH)
- Piemontite-(Sr), (CaSr)(AlAlMn3+)O[Si2O7][SiO4](OH)
- Tweddillite, (CaSr)(Mn3+AlMn3+)O[Si2O7][SiO4](OH)