Quartz is one of the hardest and most common minerals on Earth. Because of its strength and abundance, quartz is a popular and reliable choice for countertops. Quartz countertops are sometimes referred to as “engineered” or “man-made,” but quartz is in fact a natural stone. The amount of natural quartz in a slab depends on the quartz manufacturer. Cambria is among the highest concentration of pure quartz to ensure strong, compact slabs.