Chloritoid is a metamorphic mineral commonly found inside phyllite rocks – which is shale (a type of mudstone containing clays, silts and muds) that has been metamorphosed several times. Confusingly, chloritoid does not actually contain the element chlorine but instead is an iron magnesium manganese alumino-silicate hydroxide. This particular specimen is from Lyon, France: In larger …[Read More]
GeoLog