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
Bohus granite the time of the formation of the Sub-Cambrian peneplain in the Late Neoproterozoic the rocks were at surface. Subsequently, the granites were buried in sediments and then intruded by NNW-SSE oriented basic dykes in the Permian. In the Mesozoic the rocks were subject to significant weathering resulting in the formation an irregular grand-scale relief called the Sub-Mesozoic hilly peneplain. At a smaller scale the weathering is thought to have produced numerous small rock basins now seen near the coast. Bohus granite The Bohus granite () is a type of granite that crops out along the Swedish West Coast in Bohuslän.