Porcelain is a manufactured product made from compressed clays fired at very high temperatures, which makes it dense, non-porous and extremely hard-wearing. Natural stone (sandstone, limestone) is quarried, so each slab is unique in colour and pattern. The practical differences: porcelain doesn't need sealing, resists stains and frost without effort, and has a consistent finish. Natural stone has more character and variation but needs sealing and more upkeep to look its best.