Discover the powerful marbling and intense colors acid stains can create on concrete floors, countertops or any concrete surface where you want a dramatic effect. Acid stain is a liquid coloring agent that etches and permanently changes the color of concrete resulting in a powerful and dramatic concrete surface. Acid stains provide natural earth tones that often resemble marble or stone and is a popular choice for homes and businesses that want a cost-effective solution with dramatic results. Acid stains are harder to apply but provide one-of-a kind results. Acid stains can be sealed or left unsealed and are completely UV stable.