scoria

 
Pronunciation: /ˈskɔːrɪə/

noun (plural scoriae /-rɪiː/)

[mass noun]
  • 1basaltic lava ejected as fragments from a volcano, typically with a frothy texture: chunks of black scoria [count noun]: the village lay half silted up under black scoriae and dust
  • 2slag separated from molten metal during smelting: the scoria has been expelled completely from the mercury

Derivatives

scoriaceous

Pronunciation: /-ˈeɪʃəs/
adjective

Origin:

late Middle English (denoting slag from molten metal): via Latin from Greek skōria 'refuse', from skōr 'dung'. The geological term dates from the late 18th century