Sienna is a sedimentary stone that is formed in hot springs and composed of calcite calcium carbonate. This tumbled travertine is value priced. It will contain large, unfilled voids as well as edges that are not always square nor straight due to the tumbling process. These developed when carbon dioxide bubbles became trapped during the formation of the stone. As an unfilled travertine, the pits will remain visible and unfilled until they are filled with grout during installation. As a natural stone product, it is recommended that this be sealed to extend its longevity. Due to the nature of the tumbled finish, a stone-enhancing sealer will help to accentuate the natural colors in the stone that may be subdued after going through the tumbling process. It is important and recommended that a range of these products be viewed before finalizing a purchase. This material is sold as is.