Obsidian Photos
Cochise College
Photos of Rocks        Igneous Rocks
Virtual Geology Museum       Hall of Rocks
Geology Home Page
Roger Weller, geology instructor                       

wellerr@cochise.edu    copyright 2007   

black obsidian-A
glassy igneous rock
The fragment of obsidian has a conchoidal (shell-like) fracture.
 

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