Photos of Opals
Cochise College    
Opals- Rough Opal and Specimens
Geology Home Page

Roger Weller, geology instructor     copyright 2012-R.Weller

fire opal within a lava ball-3
Boi Morto Mine, Pedro Segundo, Brazil
A bump on the smooth, outer surface of the lava ball has been eroded off,
showing the vesicular basalt below the surface. 
This is a very unusual mode of occurrence for opal.

opal                                                                                                                                                    674

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
Dagbjorn Johnson
P.O. Box 50548, Santa Barbara, California 93150