Multi Dark Slate is quarried from a pit quarry in India. 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. Multi Dark Slate is manually cut, resulting in a slight variation in size between tiles. Because of this, it is not recommended that it be installed with anything less than a 1/4" grout joint. Arizona Tile does not recommend that Multi Dark 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 important and recommended that a range of this product be viewed before finalizing a purchase. As a natural stone product, it is recommended that this be sealed to extend its longevity.