Crystal Chemistry I - UA GeosciencesIf there is more Ca than the other metals, then the mineral is called calcite, or if the Fe component is greater, then the mineral is called siderite. We say that these minerals form a series. The chemical formula of the feldspar, albite, is NaAlSi 3 O 8, while it is CaAl 2 Si 2 O 8 for anorthite.