<P> Quartz is a defining constituent of granite and other felsic igneous rocks . It is very common in sedimentary rocks such as sandstone and shale . It is a common constituent of schist, gneiss, quartzite and other metamorphic rocks . Quartz has the lowest potential for weathering in the Goldich dissolution series and consequently it is very common as a residual mineral in stream sediments and residual soils . </P> <P> While the majority of quartz crystallizes from molten magma, much quartz also chemically precipitates from hot hydrothermal veins as gangue, sometimes with ore minerals like gold, silver and copper . Large crystals of quartz are found in magmatic pegmatites . Well - formed crystals may reach several meters in length and weigh hundreds of kilograms . </P> <P> Naturally occurring quartz crystals of extremely high purity, necessary for the crucibles and other equipment used for growing silicon wafers in the semiconductor industry, are expensive and rare . A major mining location for high purity quartz is the Spruce Pine Gem Mine in Spruce Pine, North Carolina, United States . Quartz may also be found in Caldoveiro Peak, in Asturias, Spain . </P> <P> The largest documented single crystal of quartz was found near Itapore, Goiaz, Brazil; it measured approximately 6.1 × 1.5 × 1.5 m and weighed more than 44 tonnes . </P>

Where can quartz be found in the us
find me the text answering this question