Definition of andesite in English:



mass nounGeology
  • A dark, fine-grained, brown or greyish intermediate volcanic rock which is a common constituent of lavas in some areas.

    • ‘Some rocks have basaltic compositions similar to the well-studied meteorites thought to have come from Mars, but other rocks are more like the volcanic rock andesite.’
    • ‘They are marked by eruptions of cooler, stickier lavas such as andesite, dacite and rhyolite.’
    • ‘The volcanic strata consist of sheet-like flows of andesite, dacite, basalts, and trachybasalts that are interbedded with agglomerates and tuffs.’
    • ‘The main slivers of Devonian rocks found within the fault zone in the Rhynie area are sandstones and andesite in the Rhyme block and the Longcroft Tuffs in the Windyfield block.’
    • ‘The clasts range from angular to subrounded and show a weak preferred orientation when elongate; they include micaceous siltstone, fine-grained sandstone, tuffaceous rock, andesite and medium-grained diorite.’


Mid 19th century: named after the Andes mountains, where it is found + -ite.