Sandstone also has a distinct bed direction, and large chips can be taken off when going with the bed. Limestone is composed primarily of the mineral calcite, or calcium carbonate. It is easy to carve and will take small detail work, but is also strong enough to support undercutting. While it does not have the innate beauty of other stones, a wide variety of textures can be created that can really bring the stone to life. Limestone can be polished, but the polish will not last outdoors.
Limestone seems to survive acid rain better than marble, so is a good choice for outdoor sculpture.