Crystals of ferberite, a mineral in the wolframite group, of which it is the ferrous pole. A selection of specimens of this crystallized mineral species. Ferberite 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 ferberites are for sale. Wolframite was formerly known as “wolfram”. It is an iron tungstate, chemical formula FeWO₄, monoclinic crystal system.