Sunstone is also known as aventurine feldspar. Stones exhibit an optical phenomenon caused by tiny reflective inclusions of the minerals goethite or hematite.
The effect is known as 'aventurescence'.
The fine gem-grade material known as Oregon sunstone occurs in a wide variety of colours. This material tends to be mostly transparent.
The inclusions in Oregon sunstone are copper.
The sunstone used to produce tumbled stones and other decorative carvings is opaque. It's correctly known as oligoclase sunstone.
SUGILITE
