Quartz Crystal Mineralogy
A scientific discipline that is concerned with all aspects of minerals, including their physical properties, chemical composition, internal crystal structure, and occurrence and distribution in nature and their origins in terms of the physicochemical conditions of formation. ref; The Editors of Encyclopaedia Britannica , Key People: James D. Dana
Pseudo-cubic habit with elongated rhombohedral face.
Grizzly Ridge Quartz Ranch, El Dorado County, Ca.