Decomposed granite of silica sand, silt particles, and clay. Different specific granite types have differing propensities to weather, and so differing likelihoods of producing decomposed granite. The parent granite material is a common type of igneous rock that is granular, with its grains large enough to be distinguished with the unaided eye (i.e., it is phaneritic in texture); it is composed of plagioclase feldspar, orthoclase feldspar, quartz, mica, and possibly other minerals. The chemical transformation of feldspar, one of the primary constituents of granite, into the clay mineral kaolin is one of the important weathering processes. The presence of clay allows water
Forbach Granite (at the time the formation of the stone). Forbach Granite is a bright mica, coloured from gray to pink. Forbach Granite includes the following minerals. 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