Axinite crystals, a selection of specimens of this crystallized mineral species. Axinite is a mineral, and here you’ll find a number of collectors’ items, each with a description, one or more photos and sometimes a video. These axinites are for sale. It is a silicate, a subgroup of the sorosilicates, more precisely a borosilicate with the chemical formula Ca2(Fe,Mg,Mn)Al2[BO3OH,Si4O12], and the triclinic crystal system.