Polished concrete is concrete that has been processed through a series of mechanically ground "polishing/grinding" steps utilizing professional equipment designed for concrete polishing. This process also includes the use of a penetrant chemical known as a hardener. The concrete densifier/hardener penetrates into the concrete and creates a chemical reaction to help harden and dust proof the surface. During concrete polishing, the surface is processed through a series of steps (in general a minimum of 6 grinding steps of processing is considered polished concrete) utilizing progressively finer grinding tools. The grinding tools are progressive grits of industrial diamonds in a bonded material such as metal/hybrid/resin often referred to as diamond polishing pads. Polished Concrete is a "Green" flooring system and LEED approved. Concrete is not considered polished before 800 grit, and it is normally finished to either the 800, 1500 or 3000 grit level. Dyes designed for concrete polishing are often applied to add color to polished concrete as well as other options such as scoring, creating radial lines, grids, bands, borders, and other designs.