Travertine is a sedimentary rock similar to limestone exhibiting earthy tones and striations with open voids or spaces. These can be relatively large and may need to be filled in with cement or resins before installation or during maintenance. Composed primarily of calcium carbonate in shallow freshwater bodies and hot springs, travertine may also contain fossilized land artifacts including plant and animal components. Very porous and soft, travertine is easy to work with and easily damaged. Care must be taken to protect the stone in high traffic or high use areas, and from acidic exposure.