Formula: (Mg,Fe)9 ((Si,Al)8O20)(OH)10.nH2O Orthorhombic
Description: Corrensite is a mineral formed from regular interlayers of chlorite with either vermiculite or smectite. It forms during low grade or hydrothermal metamorphism of basaltic rocks.
IRON COUNTY: Corrensite is found pseudomorphically replacing primary elongated crystals several cms. long of an unknown zeolite in amygdules in a basaltic rock in a quarry west of Hurley, Wisconsin. Associated minerals are calcite, chlorite and (Cordua, 2011).