Definition of pumicite in US English:

pumicite

noun

Geology
  • A volcanic ash with a composition similar to pumice but deposited as powder or granules, widely used in the manufacture of lightweight concrete and for its abrasive properties; unconsolidated volcanic ash.

Origin

Early 20th century. From pumice + -ite. Perhaps compare French pumicite pumice.

Pronunciation

pumicite

/ˈpʌmɪsʌɪt/