This barite (baryte) is from the White Pine Mine in Ontonagon County, Michigan, USA. This mine is famous for producing a variety of outstanding copper, silver and associated mineral and crystal specimens. Barite is a sulfate mineral containing the elements Ba, S, and O. This is a transparent, prismatic, crystal with micro copper crystal inclusions just below the surface. It has a vitreous to glass luster. It came from an old collection and I don’t know how prevalent the combination is. I have not seen similar specimens. It is a thumbnail sized specimen that measures 16 x 6 x 4 mm.