Ludowici Roof Tile Inc., New Lexington, Ohio, offers Celadon Ceramic Slate. For more than 400 years, the Ludowici name has been synonymous with the world’s finest clay roof tile. These centuries of craftsmanship and technological expertise were brought to bear in the development of Celadon, the world's first “ceramic slate.” Combining the fired-in strength of ceramic tile with the beauty and texture of natural slate, Celadon Ceramic Slate occupies a roofing category all its own.