Aventurescence | Described as a Metallic Glitter
Aventurescence is an optical reflectance that can be seen in certain gemstones. It's best described as a metallic glitter caused by minute plate-like mineral inclusions which can be so numerous they can even influence the colour of the gemstone.
As light reflects off the inclusions at specific angles a kind of spangled reflection can be seen.
Some of the minerals in which the optical phenomenon aventurescence can be seen include aventurine and sunstone also known as aventurine feldspar. In sunstone the aventurescence is caused as light reflects off minute inclusions of copper within the stone.
The word aventurescence is also also used to describe the optical effect that can be seen as light reflects off the flecks of copper embedded within the man-made material known as goldstone.