Our black surface plates have a significantly higher density and are up to three times as stiff. Therefore, a plate made of the Tru-Stone black does not need to be as thick as a granite plate of the same size to have equal or greater resistance to deflection. Reduced thickness means less weight and lower shipping costs.
Beware of others who use lower quality black granite in the same thickness. As stated above, properties of granite, like wood or metal, vary by material and color, and is not an accurate predictor of stiffness, hardness, or wear resistance. In fact, many types of black granite and diabase are very soft and not suitable for surface plate applications.