It's hard to answer this as stated, but for starters, try using a surface layer to provide the color of the fake stone, not the distribution shader. You can use the color checkbox of the surface layer to provide a single color, or uncheck it and connect a color power fractal (with dispacement unchecked under the displacement tab if you just want to look at the color) to the child input of the surface layer. then use this approach to try again with your blending shader. Good luck -Bill