Andradite
Image: Darla Sondrol (CC0)
Mineral NameAndradite
Chemical FormulaCa3Fe2Si3O12
Mohs Hardness6.5
Crystal Systemcubic
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity3.85
Colorsblack, dark green, yellow, brownish-red
Transparencytranslucent
Type LocalityItaly
Mineral GroupSilicates
Usesgemstone, collector
Associated Mineralsepidote, diopside, calcite, magnetite
Raritycommon
Description
This image displays dark, well-formed Andradite crystals, approximately 1 cm across, exhibiting the characteristic dodecahedral (12-sided) habit typical of garnets.
Geological Context
Andradite typically forms in contact metamorphic rocks, particularly skarns, where calcium-rich sediments react with iron-rich fluids, and also in some serpentinites and igneous rocks.
