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scoria vs. pumice

scoria
[skawr-ee-uh, skohr-] / ˈskɔr i ə, ˈskoʊr- /

noun

  • scoriae
    plural

  1. Metallurgy. the refuse, dross, or slag left after melting or smelting metal; scum.

  2. Geology. a cinderlike basic cellular lava.

pumice
[puhm-is] / ˈpʌm ɪs /

noun

  1. Also called pumice stone.  a porous or spongy form of volcanic glass, used as an abrasive.

verb (used with object)

  • pumices,
    present (3rd person singular)
  • pumiced,
    past participle,  past
  • pumicing
    present participle

  1. to rub, smooth, clean, etc., with pumice.