Roger Weller, geology instructor
firstname.lastname@example.org copyright 2010-R.Weller
common corundum crystals-1
Corundum is simply aluminum oxide. The mineral corundum typically crystallizes
in the form of hexagonal prisms with flat ends. The sides of these hexagonal prisms
are often very rough and ragged. Only if the corundum is colorful and transparent
will it be classified as ruby or sapphire.
Photo is copyright free only for non-commercial educational uses.
Just credit photo to R.Weller/Cochise College.