Onyx & Zinc

Gemstone Name: Onyx & Zinc
Location: Compressed 
Characteristics: This striking cabochon is a compressed stone composed of small chunks of Black Onyx, to which zinc has been added. The material is then heated and compressed, creating a beautiful, vivid stone.
Hardness: 5
Size: 28mm x 29mm & 4mm thick. 
Polish: Excellent