Granite general, descriptive field term for lighter-colored, coarse-grained igneous rocks. Petrographic examination is required for identification of specific types of granitoids. The extrusive igneous rock equivalent of granite is rhyolite. Granite is nearly always massive (i.e., lacking any internal structures), hard, and tough. These properties have made granite a widespread construction stone throughout human history. The average density of granite is between , its compressive strength usually lies above 200 MPa, and its viscosity near STP is 3–6·10 Pa·s. The melting temperature of dry granite at ambient pressure is ; it is strongly reduced in the presence of water, down to
Forbach Granite Forbach Granite Forbach Granite (), also called Raumünzach-Granite ("Raumünzach-Granit"), is a type of granite rock that occurs in the Northern Black Forest. It is part of the Northern Black Forest's granitic massif, to which Bühlertal granite and Wildbad granite also belong. Forbach granite predominantly outcrops in the counties of Calw and Rastatt. The most important quarrying area for Forbach granite used to be the middle Murg valley near Forbach. Today it is only quarried near Raumünzach. Forbach Granite is about 305 million years old. The stone is coarse-grained - this points to a slowly cooling of the lava / magma