Spall

The shoulder.

A chip or fragment, especially a chip of stone as struck off the block by the hammer, having at least one feather-edge.

To break into small pieces, as ore, for the purpose of separating from rock.

To reduce, as irregular blocks of stone, to an approximately level surface by hammering.

To give off spalls, or wedge-shaped chips; -- said of stone, as when badly set, with the weight thrown too much on the outer surface.