This cabochon of Gem Silica Chrysocolla is from the Inspiration Mine here in AZ. The vivid greenish blue material known as gem silica is quite rare, and high quality specimens are coveted by collectors and jewelry designers. It is also referred to by the names chrysocolla chalcedony and gem silica chrysocolla. The attraction of this gemstone is its remarkable color. The intense color is due to the presence of copper salts that penetrate the crystal lattice of colorless chalcedony. The term "gem" in "gem silica" indicates that this material is gem quality, and in fact it has a hardness of 7 on the Mohs scale and is suitable for all kinds of jewelry, including rings.
 
Flat polished beveled back
Measures 24.65x47.45mm
Thickness 4.55mm