Limestone is the end result of millions of years of the bones of sea animals and crushed sea shells that have settled on the ocean floor. You can buy limestone as a stone for building as well as for making statues because it is so durable and reliable. You’ll find limestone in varying shades of blue, yellow, black, and brown. The one thing that you need to keep in mind is that limestone can’t be polished because it’s a natural stone that isn’t crystallized.