Black tin
Black tin is the raw ore of tin, usually cassiterite, as sold by a tin mine to a smelting company. After mining, the ore has to be concentrated by a number of processes to reduce the amount of gangue it contains before it can be sold. It contrasts with white tin, which is the refined, metallic tin produced after smelting.
The term "black tin" was historically associated with tin mining in Devon and Cornwall.
