This is a non-diffusing subcategory of Category:Monoclinic crystals. It includes crystals that can also be found in the parent category, or in diffusing subcategories of the parent.

This category lists crystals that display the C2/m (No. 12) space group symmetry of the monoclinic crystal system.

The crystal being referred to may be just one of the possible forms of a named element or compound.