Apophyllite crystals, a selection of specimens of this crystallized mineral species. Apophyllite is a mineral, here many pieces of collection presented with a description, one or more photos and sometimes a video. These apophyllites are for sale. More precisely, it’s the name of a mineralogical group comprising three different species: apophyllite-(KF), with the chemical formula KCa4Si8O20(F,OH).8H2O, apophyllite-(KOH) and apophyllite-(NaF). They form continuous series between them. They are all phyllosilicates, crystallizing in the tetragonal system.