Sturmanite crystals, a selection of specimens of this crystallized mineral species.
Sturmanite is a mineral, and here you’ll find a number of collector’s items presented with a description, one or more photos and sometimes a video.
These sturmanites are for sale.
It is a calcium-iron sulfate, also containing boron, with chemical formula Ca6Fe3+2(SO4)2.5[B(OH)4](OH)12 – 25 H2O, and tetragonal crystal system.