Hexagonal crystal system

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In crystallography, the hexagonal crystal system is one of the 7 lattice point groups (see Hexagonal lattice). It has the same symmetry as a right prism with a hexagonal base. There is only one hexagonal Bravais lattice, which has six atoms per unit cell.

Graphite is an example of a crystal that crystallizes in the hexagonal crystal system.

Hexagonal arrangements have also been observed in systems of amphiphiles and constitutes one of the types of lipid polymorphism.

The point groups (crystal classes) that fall under this crystal system are listed below, followed by their representations in Hermann-Mauguin or international notation and Schoenflies notation, and mineral examples, if they exist.

name	international	Schoenflies	example
dihexagonal bipyramidal	$\mathrm{\frac6mmm}$	D_6h	beryl
dihexagonal pyramidal	$\mathrm{6mm} \,$	C_6v	greenockite
hexagonal bipyramidal	$\mathrm{\frac6m}$	C_6h	apatite
hexagonal pyramidal	$\mathrm{6} \,$	C₆	nepheline
hexagonal trapezohedral	$622 \,$	D₆	kalsilite and high quartz
ditrigonal bipyramidal	$\mathrm{\overline{6}2m}$	D_3h	benitoite
trigonal bipyramidal	$\overline{6}$	C_3h	none