First, you’ll want to use some larger grit sandpaper to lightly rough up the shiny surface of your stone so the paint will stick better. Technically, the primer that I used says you don’t have to paint for it to adhere, but to be honest, I always do anyway especially if it’s a trickier surface to get good bond between the material and the paint. Wipe up any sanding dust so the area is clean and dry.