A durable and waterproof stone, slate is comprised of mica and quartz with small amounts chlorite, hematite, and other minerals. It is typically gray and black in color, but with the presence of other minerals, hues of red, purple, and green can resonate. Slate is easily split in thin, durable sheets, therefore ideal for roofing, flagstone, high-water areas such as showers and pool areas. Most slate is available in tile form, including 12"x12" and 16"x16" tiles, although select colors come in slab form and are used for countertops and chalk boards.