Sunday, November 21, 2010

Quartz (Quartz & Chalcedony)

Chalcedony & Jasper

Smokey/Citrine Quartz

"Yellow" Jasper

Quartz is a group of minerals consisting of the "Quartz" species and the "Chalcedony" species.  Quartz Rock Crystal is basically colorless, or clear quartz.  The Quartz species has many varieties, however, because it is not only based on color.  It includes species of Quartz that are Macrocrystalline, meaning that it is made up of crystals recognizable to the naked eye.   The varieties of Quartz Rock Crystal include Smoky Quartz, Citrine, Amythest, Tiger's Eye, and more.

Quarts Cluster with mineral outer layer 
Click on Pictures to Enlarge:
Assorted "dry unpolished" agate
Assorted "dry unpolished" agate

Chalcedony is the other species belonging to the Quartz group.  It consists of cryptocrystalline Quartz, meaning that it is made up of crystals that are microscopic.  There are many varieties (and subspecies?) of Chalcedony, including Agate, Jasper, Carnelian, Bloodstone, Petrified Wood, and more.  The blue variety of Chalcedony is only considered to be "true" Chalcedony by name alone.  I believe I have seen it being sold as "Blue Lace Agate", and "Crazy Lace Agate".