9x8"

Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic. Chalcedony's standard chemical structure

Black Chalcedony is a form of Chalcedony a cryptocrystalline variety of Quartz, a silicon dioxide mineral, that is composed of sub-microscopic particles of Quartz and can be translucent to opaque in appearance. The colour range is black, dark grey/black.

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