Travertine
Travertine is a sedimentary rock. It is a natural chemical precipitate of carbonate minerals formed when carbon dioxide-rich water percolates through rocks in limestone areas. When pure, travertine is white, but often is brown to yellow due to impurities. Extensive deposits exist at Tivoli, Italy, near Rome and that was where its name comes from. Tivoli was known as Tibur in ancient roman times, and the ancient name of the stone was lapis tiburtinus meaning tibur stone, which has been corrupted to travertine.
The largest building in the world constructed largely of travertine is the Colosseum in Rome.
