A piece of tap slag of uncertain date from Roman to Post Medieval. It is dense, magnetic and black to purple in colour. It forms a thick plate which is rough and irregular on the lower face, with characteristic runs of solidified molten metal across the top face. This piece is just one small example of the many pieces recovered from the same place.

Tap-slag is slag that is 'tapped' from a bloomery furnace. This is carried out during smelting so as to allow the long continuance of the operation. It cools to a solid slag with marked flow lines. There were fewer bloomeries after the Medieval period. The presence of slag can indicate a bloomery site.

Compare to the National Slag Collection Box 006A and Box 010C which have been given medieval dates, but also other pieces in the collection date from the Iron Age onwards. Compare also CAM-A79615 and CORN-9AE021.

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