A STATEMENT OF STYLE & DESIGN. The American Slate Collection captures the unique and stunning colors of nature. This collection is an ideal choice for floors, walls and backsplashes. American Slate is a fabric of nature and a design element to enhance your lifestyle. Per Wikipedia "Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. It is the finest grained foliated metamorphic rock.[1] Foliation may not correspond to the original sedimentary layering, but instead is in planes perpendicular to the direction of metamorphic compression.