Quartz

Quartz serves as a defining element in granite and various felsic igneous rocks. Its prevalence extends to sedimentary formations, including sandstone and shale. Quartz also constitutes a common component in metamorphic rocks such as schist, gneiss, and quartzite. Notably resistant to weathering, it frequently persists as a residual mineral in stream sediments and residual soils.

While the majority of quartz crystallizes from molten magma, it also undergoes chemical precipitation from hot hydrothermal veins as gangue, occasionally accompanying valuable ore minerals like gold, silver, and copper. Remarkably large crystals of quartz are discovered in magmatic pegmatites, where well-formed specimens may attain lengths of several meters and weigh hundreds of kilograms. These diverse occurrences underscore the versatility and significance of quartz in geological processes.