Travertine , a sedimentary rock, began as limestone. The porous nature of limestone makes it a great reservoir for liquids. Heated by the Earth’s inner core, the water rises as steam or geysers. This hot water dissolves the limestone which rises to the earth’s surface forming mud beds. Time passes and the mud bed cools and crystallizes to form a solid stone called travertine.
The characteristic small holes or cavities found in travertine are a result of the cooling process. Sometimes, these holes are filled before the product is honed or polished. Fill material is generally material dust from the cutting process and mixed with hardener. Unfilled travertine is also quite beautiful and unique.
The Coliseum in Rome, having stood for over 2000 years, is perhaps the most famous travertine structure in the world. Travertine is commonly used outside as cladding and pavement, as well as inside for floors, walls and countertops.
Travertine is harder than limestone, but softer than marble and granite. Like any stone, travertine should be sealed with a penetrating sealer to prevent stains from penetrating into the stone.