Onyx is a semiprecious stone considered a variety of Agate or Chalcedony. It forms in rock cavities from the dissolution of minerals in chemically rich groundwater. Over millions of years, the layers solidify and compact to form onyx. Regarding its geographic origin, onyx is found primarily in Mexico, Brazil, Argentina, Uruguay, and parts of Asia.
 
Onyx is distinguished by its polished finish, ideal for jewellery and particularly prized for making cameos. 
 
Available in 5mm, 8mm and 10mm sizes.