Tourmaline crystals, a selection of specimens of this crystallized mineral species. Tourmaline is a mineral, here many collectibles presented with a description, one or more photos and sometimes a video. These tourmalines are for sale.
They are a group of minerals of the silicate family, cyclosilicate subgroup, with chemical formula XG3Z6(BO3)3T6O18(OH,O)3(OH,F,O), where X = (Ca,Na,K,[]), G =(Mg,Li,Al,Mn,Fe2+,3+,V,Cr,Ti,Cu,[]), Z = (Al,Mg,Cr,V,Fe3+,Ti), T = (Si,Al,B,Be), of the trigonal crystal system.