Definition of diorite in English:



mass nounGeology
  • A speckled, coarse-grained igneous rock consisting essentially of plagioclase, feldspar, and hornblende or other mafic minerals.

    • ‘Among the 30 different types of stone recognized are varieties of diorite, granite, bedded tuff, sandstones, limestones, and tufa.’
    • ‘The thrust sheet overlying the Delaney Dome Formation is composed of the basic Ballyconneely Amphibolite and interbanded quartz diorite and hornblende gneiss that intrude the Dalradian sediments.’
    • ‘It is dominated by variably foliated, medium-grained, even-textured to porphyritic biotite hornblende tonalite and quartz diorite.’
    • ‘All granitoids in the footwall of the Simav detachment are dominated by medium - to coarse-grained granite, granodiorite, quartz monzonite, diorite and syenogranite.’
    • ‘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.’


Early 19th century: coined in French, formed irregularly from Greek diorizein ‘distinguish’ + -ite.