Holmium–magnesium–zinc quasicrystal

A Ho–Mg–Zn quasicrystal in the shape of a dodecahedron.

A holmium–magnesium–zinc (Ho–Mg–Zn) quasicrystal is a quasicrystal made of an alloy of those three metals that has the shape of a regular dodecahedron, a Platonic solid with 12 five-sided faces. Unlike the similar pyritohedron shape of some cubic-system crystals such as pyrite, this quasicrystal has faces that are true regular pentagons.