Source : Webster's Revised Unabridged Dictionary (1913)

Travertine \Trav"er*tine\, n. [F. travertin, It. travertino,
   tiburtino, L. lapis Tiburtinus, fr. Tibur an ancient town of
   Latium, now Tivoli.] (Min.)
   A white concretionary form of calcium carbonate, usually hard
   and semicrystalline. It is deposited from the water of
   springs or streams holding lime in solution. Extensive
   deposits exist at Tivoli, near Rome.