Cabochon cutting
Cabochon cutting shapes a gem with a smooth, domed surface and no facets. A simple cabochon normally has a rounded top and flat base. A double cabochon is domed on both sides.
Form and optical effect
The oval is traditional, though round and freeform outlines are also used. Transparent, translucent and opaque materials may be cut this way. In some gems the dome reveals optical effects such as a cat's eye or star.
Assessment
Cabochon describes the cutting style, not the mineral or age. Examine symmetry, evenness of the dome, polish, scratches and chips. Moulded glass or plastic can resemble a natural cabochon, so material identification remains a separate question.
Source: Gemological Institute of America, Gem Cutting Styles.
