magnetite crystals, octahedral, double pyramid d, in glass dish

magnetite crystals magnetite crystal iron oxide mineral magnet magnetic octahedral ferrimagnetic pyramid shape iron fe3o4 lodestone rust brain rusty rusted granular ferrous metallic reflective ferric platonic solid ore oxides double human occurrence metal ferrous-ferric material compound substance stone geology geological mineralogy metallurgy chemistry natural reddish black glass dish isolated close-up closeup