Properties of Greywacke and Siltstone play an important role in determining the type of rock. Along with Greywacke vs Siltstone properties, get to know more about Greywacke Definition and Siltstone Definition. For the ease of understanding, the properties of rocks are divided into physical and thermal properties. Rocks have a variety of properties like hardness, color, specific gravity, fracture, cleavage, luster etc. Know all about physical and thermal properties of Greywacke and Siltstone.