Cultured marble countertops are made in an in-mold process that allows the manufacturer to make a customized shape and size for the counter. To make this product, very small pieces of ground marble are combined with resin. This mixture is then pressed together in the mold under very high pressure. This mixture then dries to form a very hard material that is stronger than regular marble. By combining the marble with the resin, you get a more dense product that still has some of the looks of a traditional marble countertop.