They crystallize in the cubic system, having three axes that are all of equal length and perpendicular to each other.

It is a soft yellowish white mineral which crystallizes in the monoclinic system.

It is a brown to black metallic mineral which crystallizes in the tetragonal system.

It is a gray white metallic mineral crystallizing in the hexagonal system.

Huttonite crystallizes in the monoclinic system with space group P2/n.

It is a deep red to greenish black mineral which crystallizes in the trigonal system.

It is a colorless to yellow mineral crystallizing in the trigonal system.

It crystallizes in the orthorhombic system, but only rarely forms distinct crystals.

Polyhalite crystallizes in the triclinic system although crystals are very rare.

It crystallizes in the isometric system, although crystals are very rare.