Roger Weller, geology instructor
firstname.lastname@example.org copyright 2011-R.Weller
The mineral calcite crystallizes in a great variety of forms.
One of these forms is the rhombohedron, the same form as the calcite cleavage.
The crystal faces are parallel to the cleavage directions.
Photo is copyright free only for non-commercial educational uses.
Just credit photo to R.Weller/Cochise College.