1 Chemical preparations for use as densifiers on concrete, masonry, stone, tile, or cementitious materials; chemical preparations for use as hardeners on concrete, masonry, stone, tile, or cementitious materials; chemical preparations in the nature of preservatives for use on concrete, masonry, stone, tile, or cementitious materials; chemical preparations for use as a stain repellent treatment on concrete, masonry, stone, tile, or cementitious materials