KEMIKO Stone Tone Concrete Acid Stain is an acid base, reactive stain. This interior/exterior reactive stain is zero VOC, UV resistant and will not chip, fade or peel. This acid stain is formulated to chemically bond with the concrete to create permanent, unique colors that simulate the look of natural stone and marble. Colors are concentrated and can be diluted with water to create variations in color intensity. 5 different stain colors to choose from.