Although both are stones and both are quarried from the earth, granite and marble (and marble’s relatives-limestone, onyx and travertine) are very different from each other.The greatest difference lies in the porosity, softness and durability of marble when compared to granite.lthough both are stones and both are quarried from the earth, granite and marble (and marble’s relatives-limestone, onyx and travertine) are very different from each other.