Travertine is a natural stone that does not contain any dyes or chemicals. The main difference between Travertine and other natural stones stems from the way they are formed. Each stone is formed through a different process and these processes impart very different characteristics in density and hardness among other things.
Travertine is formed in hot springs or limestone caves. It is formed by the precipitation of calcium carbonate. In other words, a chemical soup, like the one pictured to the left, is very high in concentration of calcium carbonate and the liquid precipitates off and the remaining mixture hardens and is compressed into the travertine stone we have today. Kind of like a natural concrete in that you have a soupy mixture that hardens.
Travertine is not the same as Marble, Granite or Limestone which is a metamorphic rock. Some of the key characteristics of Travertine stone are the holes and features in the stone which are caused by carbon dioxide evasion or CO2 bubbles in the mixture as it is setting. Metamorphic rock is a rock that has undergone changes through extreme pressure and heat. It causes the rock to change or go through a “metamorphosis” that often forms crystals in the rock giving granite that sparkling look. All gasses are forced out leaving a much denser stone.
Travertine has been used for centuries as a building material. The most famous structure built with it is the Coliseum in Rome, Italy but there are tens of thousands of buildings travertine has been used to construct. One of the most recent famous buildings would be the Getty Museum in Los Angles, California.