Minerals and Metals in Ancient India v2.c47.170

v2.c47.170

A related mineral is Saponite or Piotine. Commonly massive. In nodules, or filling cavities. Soft like fat, hence ‘piotine’, like soap hence ‘saponite’. This is hydrous silicate of magnesium and aluminium, the latter partly replacing Mg and partly Si in the sheet structure. Colour white to dark. Gives out water very readily on heating and then darkens. This is unlike talc.