The sensation of the last few years: in addition to what are probably the world's best wurtzite crystals, what are probably the world's best alabandine crystals came to light from the tanzanite mines. They have been known for a long time, the miners call them "chuma", the Swahili word for iron. They thought these crystals were rotten pyrite crystals. These crystals are a combination of cube and octahedron, the unusually large number of vicinal faces are interesting.
