difference between quartz and quartzite? Quartz and quartzite are distinct materials often confused due to their similar names. Quartz is a mineral composed of silicon and oxygen atoms in a continuous framework of SiO₄ silicon–oxygen tetrahedra. It's commonly used in countertops and decorative pieces due to its durability and variety of colors. Quartzite, on the other hand, is a metamorphic rock formed from sandstone under heat and pressure.