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

Roger Weller, geology instructor     copyright 2012-R.Weller

Australian boulder opal-polished-2
Boulder opal is a thin layer of fire opal on a brown rock.

opal                                                                                                                                                                         boulder21

Photo is copyright free for non-commercial educational uses. 
Just credit photo to R.Weller/Cochise College

Specimen in memory of Ray Dunn.