spall

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A chip, fragment, or flake from a piece of stone or ore.
• intransitive verb To break up into chips or fragments.
• intransitive verb To chip or crumble.

from The Century Dictionary.

• noun A chip or splinter thrown off, as in chopping or hewing; now specifically, in masonry, a piece of stone chipped off by a blow of a hammer or mallet.
• To split; splinter; chip; specifically, in mining, to chip or break up roughly, as ore, preparatory to sorting the material.
• To keep (the frames of a ship) at their proper distance apart.
• To splinter; chip; give off spalls.
• noun The shoulder.

from the GNU version of the Collaborative International Dictionary of English.

• noun obsolete The shoulder.
• transitive verb (Mining) To break into small pieces, as ore, for the purpose of separating from rock.
• transitive verb (Masonry) To reduce, as irregular blocks of stone, to an approximately level surface by hammering.
• noun A chip or fragment, especially a chip of stone as struck off the block by the hammer, having at least one feather-edge.
• intransitive verb 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun obsolete, rare The shoulder.
• noun A splinter, fragment or chip, especially of stone.
• verb transitive To break into fragments or small pieces.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a fragment broken off from the edge or face of stone or ore and having at least one thin edge