Roger Weller, geology instructor
firstname.lastname@example.org copyright 2010-R.Weller
corundum-rubies and sapphires
Rubies are red corundum. All other colors of corundum are classified as sapphires.
These water-worn crystals of rubies and sapphires are each less than one
centimeter in diameter.
Photo is copyright free for non-commercial educational uses.
Just credit photo to R.Weller/Cochise College.