A fantastic and very attractive combination specimen. This piece has outstanding aesthetics and contrast. It has a great association of incredibly sharp, mirror bright, highly lustrous, gemmy, crystals of Cassiterite (almost all crystals are twinned) measuring up to 2.3 cm. with gemmy prismatic crystals of Quartz. It is a very good small cabinet size specimen. This is an attractive piece and one of the better ones for associations that I have seen from the locality. There is some very slight damage to the specimen, but it is incredibly difficult to find pieces from this mine that have no damage. This Viloco is the most classic locality for Cassiterite in Bolivia, and was the source of a large amount of tin provided for the United States during WWII. Valued at $750-950. As far as matrix specimens for this size and quality, you are looking at what is today a very rare thing and aesthetically impressive as well, so the value my friend put on it when he consigned it to me (above) is in my opinion low. 5.8 x 4.3 x 3.7 cm