Rustic Gold Slate is a sedimentary stone. Millions of years ago, silt and mud from a river deposited soil at the mouth of a larger body of water, giving this stone its random color variation. As a natural stone product it is recommended that it be sealed to extend its longevity. Due to the nature of the tumbled finish, a stone-enhancing sealer will accentuate the natural colors in the stone that may be subdued after going through the tumbling process. Arizona Tile does not recommend that Rustic Gold Slate be installed in or near wet areas, such as showers or next to a swimming pool, because this stone has the potential to oxidize and rust. There will be noticeable variations in color and movement between pieces. Therefore, it is recommended that a range of this product be viewed before purchasing.