Epidote
Image: Raimond Spekking (CC BY-SA 4.0)
Mineral NameEpidote
Chemical FormulaCa2Al2Fe3+(SiO4)(Si2O7)O(OH)
Mohs Hardness6
Crystal Systemmonoclinic
Lustervitreous
Streak Colorgrayish white
Cleavageperfect on {001}, good on {100}
Fractureuneven to conchoidal
Specific Gravity3.35
Colorsdark green, pistachio green, yellowish green, brownish green, blackish green
Transparencytransparent to translucent to opaque
Type LocalityMinas Gerais, Brazil
Mineral GroupSorosilicates
Usescollector's specimens, minor gemstone
Associated Mineralstitanite, albite, quartz, feldspar, garnet
Raritycommon
Description
This specimen features dark green to blackish-green, prismatic Epidote crystals, some with well-defined faces, associated with lighter-colored Albite and yellowish Titanite.
Geological Context
Epidote commonly forms in regionally metamorphosed rocks (e.g., greenschist facies), contact metamorphic rocks, and hydrothermally altered igneous rocks. It is also found in veins and as an alteration product of plagioclase feldspar.
