Non-metallic building materials, namely, limestone for use in facades, floor coverings, staircase installations, and for overall interior design of buildings; building materials of limestone for use as parts of facades, floor covering, or staircases; Non-metallic building materials, namely sandstone for use in facades, floor coverings, staircase installations, and for overall interior design of buildings; building materials of sandstone for use as parts of facades, floor coverings, or staircases