Cassiterite with Tourmaline

The Viloco Mine (sometimes called Araca) for many years has stood as one of the top Cassiterite localities in the world. This mine is still active today and bears the unique distinction of producing the only GEM quality (facet grade) Cassiterites from any mine in Bolivia. Considering the millions of tons of tin ore that Bolivia has yielded, the fact that only one mine ever produced transparent Cassiterite is remarkable.

This piece is a good, lustrous, sharp, black to very dark golden colored cyclic twinned crystal group which is associated with small acicular crystals of rarely seen greenish-brown Tourmaline. Only a small percentage of the Cassiterites from Viloco are associated with Tourmaline. I photographed the Tourmalines under the microscope to better illustrate their unique nature. A cool association specimen from this classic locality.

Specimen # BOL711B163