chatoyant

adjective

1. changing in luster or color: chatoyant silk.
2. Jewelry. reflecting a single streak of light when cut in a cabochon.

noun

3. Jewelry. a cabochon-cut gemstone having this reflected streak, as a chrysoberyl cat’s-eye.

adjective

1. having changeable lustre; twinkling
2. (of a gem, esp a cabochon) displaying a band of light reflected off inclusions of other minerals

noun

3. a gemstone with a changeable lustre, such as a cat’s eye