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. largest in California, and the largest west of the Rocky Mountains. In 1980, Granite Rock submitted to the Forest Service a five-year plan to remove substantial amounts of limestone from a quarry on the south face of Pico Blanco within the National Forest boundary. The Forest Service prepared an Environmental Assessment of the plan and recommended some modifications, which Granite Rock implemented. When Graniterock obtained the permit in 1983, it began to excavate a open pit mine. The California Coastal Commission required Granite Rock to apply for a coastal development permit for any mining undertaken after the date of notification.