Definition of quartz in US English:



  • A hard white or colorless mineral consisting of silicon dioxide, found widely in igneous, metamorphic, and sedimentary rocks. It is often colored by impurities (as in amethyst, citrine, and cairngorm).

    • ‘Other minerals found here are the red ochre, soap stone, white quartz and molding sand.’
    • ‘Late chlorite and carbonates overgrew the schistosity defined by phengite, chlorite and quartz.’
    • ‘The white material is quartz and the black is the wall rock from the edge of the vein.’
    • ‘Because they formed within the peat, coal balls generally contain very little detrital clay minerals and quartz.’
    • ‘These soils have a typical, immature tropical soil mineral assemblage dominated by kaolin, quartz and goethite.’
    • ‘Some topaz forms spectacular crystals and matrix specimens on magnesite or quartz.’
    • ‘The siltstones are composed of angular quartz and rare feldspar, set in a finer matrix that locally contains some calcite.’
    • ‘The intervening area is dominantly a mixture of clay and quartz.’
    • ‘As a result, quartz is an uncommon gangue mineral within most of the district.’
    • ‘The grey colour of quartz is a mineralogical standard showing that the thickness is correct.’
    • ‘The sample is strongly foliated and consists of garnet, biotite, quartz, plagioclase and cordierite.’
    • ‘Mylonitic rocks usually have ribbon quartz and rotated albite porphyroclasts.’
    • ‘Outside we saw large tables covered high with specimens of kyanite in quartz.’
    • ‘These granite dikes are composed almost totally of potassium feldspar and quartz.’
    • ‘Adjacent to the gray quartz with acanthite and gold is sugary white quartz with massive galena.’
    • ‘My necklaces are made mainly of semiprecious stones, such as agate, quartz, amber, rock crystal and jade.’
    • ‘There is much chlorite growth, but quartz is only very poorly recrystallized.’
    • ‘All three are dominated by unaltered muscovite, quartz, K-feldspar and albite, with minor epidote.’
    • ‘Where pyrite crystals have been lost, it can be seen that quartz did not penetrate pyrite.’
    • ‘The ore zone is a combination of veinlets, lenses, and nests of pyrite and quartz.’


Mid 18th century: from German Quarz, from Polish dialect kwardy, corresponding to Czech tvrdý ‘hard’.