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
California Coastal Comm'n v. Granite Rock Co. The Coastal Commission did not seek to prohibit mining of the unpatented claim, only to regulate mining activity in accordance with the detailed requirements of the California Coastal Act. Granite Rock filed an action in U.S. District Court claiming that the Coastal Commission permit requirement was preempted by Forest Service regulations, by the Mining Act of 1872, and by the Coastal Zone Management Act. The District Court denied Granite Rock's motion for summary judgment, and dismissed the action. The Court of Appeals for the Ninth Circuit reversed the lower court's decision, holding that the Coastal Commission permit requirement was preempted