TRAVERTINE:   Travertine - a sedimentary rock, travertine is a type of limestone that formed by evaporation of hot water containing dissolved calcium, thus leaving
finely crystallized calcite deposit. These deposits accumulated in horizontal layers
over thousand of years. The holes in travertine are the pathways for the water
as it passed up from the geothermal spring below. Its natural color is white.
The other colors come from chemicals in the water and other debris, including
ash from fires and volcanoes, animal remains and vegetation. Travertine is
very durable, often used for exterior wall cladding and paving installation
around the world.