Aventurine quartz contains inclusions of small crystals that reflect light, and which give a range of colours – depending on the nature of the inclusion. Green aventurine quartz has platy inclusions of green fuchsite mica; pyrite inclusions give a brown colour; a greenish brown variety may be due to the mineral goethite. Other inclusions give bluish white, bluish green or orange varieties.
Aventurine quartz is found in Brazil, India and Russia. Other localities include United States, Japan and Tanzania.
Aventurine quartz has been confused with aventurine feldspar, amazonite and jade. A simulant, known as goldstone, has been made to imitate both aventurine quartz and aventurine feldspar. It contains small triangles and hexagons of copper held in glass. With a x10 hand lens it should be possible to see the outlines of the copper spangles.