non-metallic building materials, namely, semi-worked woods; non-metallic rigid pipes for building; asphalt, pitch and bitumen; non-metallic transportable buildings; monuments, not of metal; aquaria structures, namely, aquarium gravel, decorative aquarium stones, chemically treated lumber for aquatic uses; alabaster; roof flashing, not of metal; angle irons, not of metal; roofing tiles, not of metal; lintels, not of metal; slate; roofing slates; clay, namely, clay ash, clay flooring, clay scul...