Pera Tile SIL-GREIGE RIGATO 24″ x 48″ Porcelain Silky Stone: Greige Rigato 15.52 Square Feet per Case. Silky Stone achieves limestone effect using digital technology. Inspired by the look and feel of nature combined with the practicality of modern architecture, Silky Stone is the result of a sophisticated balance between essentiality and minimalism. Silky Stone’s almost perfect flatness and precise grinding conceals the joints, creating continuity on surfaces using porcelain stoneware.