Quartzite is a non-foliated metamorphosed pure sandstone subjected to contact or regional metamorphism. It is mainly composed of quartz due to its quartz-rich sedimentary protolith in which the grains are recrystallized into coarser, equigranular crystals from intense heat and pressure. Though it experiences direct pressure, the metamorphic intensity creates a gritty, interlocking texture similar to that of marble, which can be observed by the naked eye in the magnified image. Pure quartzite typically occurs as white or grey but can vary in colour from shades of pink, brown, green, and yellow due to impurities, seen in this sample. These impurities may have been pre-existing in the sandstone rock before undergoing metamorphism or migrated into the grain crevices during recrystallization, like the pyrite shown in this sample. In a hand sample, quartzite can appear very similar in texture to unmetamorphosed quartz-rich sandstone and marble. Physical characteristics that differentiate quartzite from these other rocks are its conchoidal-like fracture across quartz grains instead of along grain boundaries, which tells it apart from sandstone. Quartzite has a hardness greater than 7 whereas marble can be scratched by a metal blade. Quartzite will not effervescence in reaction to hydrochloric acid, easily distinguishing it apart from calcium carbonate marble. Quartzite is highly associated with orogenic events and commonly found in folded mountain ranges. It typically forms in convergent boundary settings where sandstone is deeply buried and subjected to medium to high-grade metamorphism. Its occurrence in high altitude settings is due to greater resistance to physical and chemical weathering than that of the surrounding material, leaving it exposed as mountain ridges or fragmented as scree on mountain slopes.