Dolomite is a kind of carbonate rock that is similar to limestone, but is generally heavier and harder than that type of sedimentary rock. Due to their analogous nature, dolomite is often utilized in place of limestone in a variety of applications, especially as an aggregate in cement mixes. The rock also gains frequent use as a building stone, and when it undergoes metamorphism it becomes dolomitic marble, which is popularly utilized for ornamental purposes. However, due to the beautiful colors and variegated forms it exhibits and the good polish it may take even in its unchanged form, dolomite that has not metamorphosed is also frequently sold as marble.