Roger Weller, geology instructor
email@example.com copyright 2012-R.Weller
Shell and internal cavity were replaced by fire opal.
Photo is copyright free for non-commercial educational uses.
Just credit photo to R.Weller/Cochise College.
Opal specimen courtesy of Opex Opal
Specializing in precious opals and opal jewelry
P.O. Box 50548, Santa Barbara, California 93150