Datolite crystals, a selection of specimens of this crystallized mineral species. Datolite 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 datolites are for sale. It’s a silicate, from the mesosilicate subgroup, specifically a hydroborosilicate, with the chemical formula CaB(SiO4)(OH) with traces of: Mn, Mg, Al, Fe and a monoclinic crystal system.