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
Wave Rock land surface. This process formed underground "domes" of solid granite bedrock surrounded by deeply weathered, relatively loose, and disaggregated granite. Following separation of Australia and Antarctica and accompanying tilting of what became southwestern Australia, periodic erosion of the deeply weathered granite, which underlaid the surrounding land surface, exposed these buried solid bedrock domes over time as Hyden Rock. Wave Rock is a spectacular example of what geomorphologists call a "flared slope". A flared slope is a concave-upward or -inward bedrock surface that is typically found around the base of inselbergs, bornhardts, and granitic boulders and also on their higher slopes.