Polonium tetrachloride is either monoclinic or triclinic. In total there are seven crystal systems&colon; triclinic, monoclinic, orthorhombic, tetragonal, trigonal, hexagonal, and cubic. In total there are six crystal families&colon; triclinic, monoclinic, orthorhombic, tetragonal, hexagonal, and cubic. Crystals grown from vapor in vacuum can be monoclinic, triclinic, and orthorhombic motifs. Gibbsite and bayerite are monoclinic, whereas doyleite and nordstrandite are triclinic forms. Orthorhombic, monoclinic, and triclinic crystals can show three and are trichroic. Chabazite crystallizes in the triclinic crystal system with typically rhombohedral shaped crystals that are pseudo-cubic. The dihydrate has a triclinic structure, while the trihydrate has a monoclinic structure. It is found in the compound AuXe(SbF), which exists in triclinic and tetragonal crystal modifications. At yet lower temperatures, microcline, a triclinic polymorph of potassium feldspar, is stable. Amesite crystallizes in the triclinic crystal system. The mineral crystallizes in the triclinic crystal system. It crystallizes in the triclinic system typically occurring in radiated or fibrous crystalline masses. Oligoclase is a high sodium feldspar crystallizing in the triclinic system. It forms brown to black triclinic lamellar crystals.