spalling

/S P AO1 L IH0 NG/
verb
  1. 1

    To break into fragments or small pieces.

  2. 2

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

noun
  1. 1

    The process of reducing (stone blocks, etc.) to an approximately level surface by hammering.

  2. 2

    A fragment or chip of stone.

Source: https://en.wiktionary.org/wiki/spall, https://en.wiktionary.org/wiki/spalling