Why does marble have beautiful patterns?

The natural marble has beautiful patterns that can be compared with those drawn manually. This is because marble was bred in the sea, and there are a lot of animals and plants living on the sea floor, which will leave a lot of remains after death. After many years, due to the movement of the submarine crust, they were buried deep underground and had geological changes together with other kinds of calcium carbonate. The calcium carbonate gradually turned into white limestone, and the remains of animals and plants were sandwiched in the rock, forming black limestone. The two colors of rocks interlace to form a marble with beautiful patterns. Because marble is easy to cut, it was used as carving and building materials long ago.