Rhyolite 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

rhyolite, cut surface
Rhyolite is a high silica fine-grained (aphanitic) igneous rock.
The best way to describe this particular specimen of rhyolite is that
it closely resembles bologna that has turned brown and hardened.
It is also porphyritic; the small clear inclusions are crystals of sanidine feldspar.

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