Home > African Minerals – April 25 > MS1196 Calderite

Calderite - Sold

Calderite is a rare member of the garnet group having ideal composition Mn2+3Fe3+2(SiO4)3. While its validity was debated in the literature for decades, Dunn (1979) finally affirmed the validity of calderite using material from this locality. Amthauer et al. (1989) further studied material from this locality and identified compositional trends. Calderite forms in a metamorphic manganese-rich environment, at relatively high pressures and low temperatures. This specimen is a partial crystal of calderite with minor inclusions of a manganese oxide (likely braunite), showing one 5.4 cm wide crystal face. This specimen comes from Charlie Key dealer stock, released in 2007. Perhaps this specimen might yield some unusual (but far from flawless) gemstones.