Travertine like sandstone and limestone, is a sedimentary rock. It is formed near hot springs and rivers. Composed mainly of calcium carbonate, it is semi crystalline and fairly hard. Travertine deposits are usually found with naturally occurring holes and can be supplied with these holes either filled or unfilled in honed or polished finishes. Travertine is very popular with architects and interior designers for flooring, cladding and paving.