1. Education

Cairngorm

Quartz and Silica Minerals Picture Gallery

Cairngorm, named for a Scottish locality, is the dark brown variety of smoky quartz. Its color is due to missing electrons, or holes, plus a whisper of aluminum.
Brown smoky quartz
Photo (c) 2012 Andrew Alden, licensed to About.com (fair use policy)
See More About

©2013 About.com. All rights reserved.