Cassiterite (rough and cut set)
Thumbnail, 2.1 x 1.8 x 1.5 cm (Crystal), 13.50 ct (Gem)
Viloco Mine, La Paz, Bolivia

2.1 x 1.8 x 1.5 cm (Specimen); 13.50 carats; 11.47 mm x 8.96 mm (Gem) - Cassiterite is a well known tin oxide, and faceted stones are appreciated in the collector world for their beauty as most of the Cassiterite in the world is black and opaque, so gem material is scare despite the fact that the species is found all over the world. This rough and cut set actually comprises two pieces from opposite sides of the world as the crystallized half is a wonderful represenation of the famous specimens from the Viloco Mine above La Paz, Bolivia. This mine incidentally is the only locality in Bolivia where good gem crystals of Cassiterite can be found, despite the fact that the mineral is found in literally hundreds of places in Bolivia. The crystals on the specimen are sharp and lustrous with a deep golden-brown interior color, and a small Quartz crystal association for a nice touch. The gemstone in this duo is actually from Sri Lanka with a gorgeous "Step Cushion" cut and brilliant internal flashes of amber, root beer, and cognac and superb clarity for the size. Together they make a wonderful set and a worthwhile acquisition for anybody who collects rough and cut sets.