Quartz Crystal Mineralogy

    Mineralogy  is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization.  (wiki)
 

Quartz

 Pseudo-cubic habit with elongated rhombohedral face.

Quartz Crystal

Grizzly Ridge Quartz Ranch, El Dorado County, Ca.