Travertine is formed by the calcium carbonate deposits from the water of mineral hot springs. When water percolates through the earth and rock in limestone areas the water dissolves the limestone and becomes saturated with the calcium carbonate. When this saturated water is released to the hot spring, the water evaporates, a gas is released and the residue are crystals of calcium carbonate that build up layer upon layer. The gas released forms small pockets or holes in this layering process. Over time layers harden and become known as Travertine. Travertine is used extensively for cladding, landscaping, flooring, sculpture and furniture.