- Cassiterite, Siderite
- Miniature, 4.0 x 3.3 x 2.2 cm
- Viloco Mine (Araca mine), Loayza Province, La Paz Department, Bolivia
Bolivia has probably produced more tin than any other country in the world. The great tin mines at Viloco (sometimes called Araca) have produced some of the most magnificent Cassiterite specimens extant. This particular specimen hosts several fine, sharp, highly lustrous, black-brown cyclic twinned crystals of Cassiterite measuring up to 9 mm with Quartz crystals and tan Siderite "discs".