Definition of porcellanite in English:

porcellanite

(also porcelanite)

Pronunciation /pɔːˈsɛlənʌɪt/

noun

Geology
  • Originally: a hardened clay or shale resulting from thermal metamorphism; also called porcelain jasper. Later also: any dense siliceous rock with an appearance resembling unglazed porcelain.

Origin

Late 18th century; earliest use found in Richard Kirwan (1733–1812), chemist and mineralogist. From German Porzellanit (attributed to J. T. A. Peithner by Kirwan) from Porzellan + -it.