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
Granite Mountain (Texas) Granite Mountain (Texas) Granite Mountain is a solid dome, also known as a bornhardt, of pink granite (pink granite is also known as Sunset Red) rising over 860 feet one mile west of Marble Falls, Texas. Since quarry operations began in the late 19th century, the distinctive pink-red colored rock has been used in the construction of the Texas State Capitol in Austin, Texas, and also for the construction of the Galveston Seawall. The mountain no longer looks like a geographic feature because of the heavy mining, which has fully covered its surface. A similar but much larger area known