Definition of phonolite in English:



mass nounGeology
  • A fine-grained volcanic igneous rock composed of alkali feldspars and nepheline.

    • ‘South of the city of Isparta pyroclastic rocks are interbedded with rhyolite, trachyte, phonolite and lamproite flows (the Golcuk and Bucak Volcanics of Savascin et al.).’
    • ‘In the Canaries, the lavas are much more compositionally varied in each of these stages, ranging from tholeiitic basalts to phonolites and trachytes.’
    • ‘The dominant magma types are basalts and hawaiites, with lesser amounts of trachytes, quartz trachytes, alkali rhyolites and phonolites.’
    • ‘Plagioclase dramatically removes Sr at intermediate stages and alkali feldspars sequester Ba and Rb as late-stage trachytes and phonolites form in alkaline magmas.’


Early 19th century from phono-‘relating to sound’ (because of its resonance when struck) + -ite.