View source for Geometric crystal class

<font color="blue">Classe cristalline géométrique</font> (''Fr''); <font color="red">Geometrische Kristallklasse</font> (''Ge''); <font color="green">Clase cristallina geométrica</font> (''Sp''); <Font color="black"> Classe cristallina geometrica </Font>(''It'').　<Font color="purple"> 幾何晶族 </Font>(''Ja'')


== Definition ==

'''Geometric crystal classes''' (or simply 'crystal classes') classify the symmetry groups of the external shape of macroscopic crystals, namely according to the morphological symmetry. There are 10 two-dimensional geometric crystal classes and 32 three-dimensional geometric crystal classes, in one to one correspondence with the 10 and 32 point groups in ''E''<sup>2</sup> and ''E''<sup>3</sup>, respectively.

== See also ==
*[[Arithmetic crystal class]]
*Section 8.2.4 of ''International Tables for Crystallography, Volume A''<br>


[[Category:Fundamental crystallography]]