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 consists of several superb quality, sharp, highly lustrous, very dark brown (essentially black) cyclic twinned crystals measuring up to 2.3 cm which are associated with minor Siderite blades and a few Quartz crystals.