We purchased this mortar and pestle set because the merchant assured us that this so called "stone" is in fact white marble. White marble is mostly made of calcium carbonate, and we consider this material to be non-toxic in comparison to other materials often used to produce mortar and pestle sets. Since the stone here is also light colored, we suspect that the possibility of presence of toxic metals and elements might also be rather small when compared to dark-colored stone. This mortar is about 6 inches in diameter, which we like, but we would have purchasd a bigger white marble mortar if there would have been one sold. This was the biggest white marble mortar that we could find anywhere, so we got it, and love it. As a side note, the bottom of the base is lined with a round rubber mat, which is good in general; however, the diameter of the mat is a bit smaller in size relative the the diameter of the base. This difference in diameter makes the mortar less sturdy during use. The general design might have been more sturdy with a slightly wider base.