​BLACK TIN, in mineralogy, a term given to tin-ore when it is ready to be melted into metal, after having been well stamped, washed, and dressed. It is taken up from the washing-troughs in the form of a tine black powder, and from this circumstance is called black tin; two pounds of which being melted, will produce one pound of white tin. The principal mines from which this useful metal is obtained in Britain, are those in Cornwall.—See Tin.