Out of all the limestone/calcium carbonate fillers I've used around the world, Specialty Minerals in Lucerne Valley has the best. Their 30/80, mixed 50/50 makes a perfect viscosity (@25% resin) and the color, as it is, without using titanium, is an incredibly beautiful natural brown paper bag color for a cultured marble background. I see people using a ton of pigments to get what this product does naturally. Simply using this color for the background, mixed dry, with some white veining makes a nice, natural looking cultured marble. You can see some cultured marble finished products at www.culturedmarblemolds.com read more