Two mica syenogranites of Gabal El Esh being emplaced into Dokhan volcanics. These leucogranites are peraluminous in composition, Fe-rich sub-alkaline with low contents of Ba and high contents of Rb and k2O. These facts substantiate the geochemical characteristics of S-type granites. They contain both orthoclase perthites and plagioclase; thus, they can be classified as subsolvus granites. Placer feldspars are the youngest unit in the area and represented by surficial cover in the main dry wadis and their tributaries.
Placer feldspars can be used as a new material for ceramics and sanitary wares. It is naturally occurring blend of feldspars and quartz resulting from the erosion of particular kind of granitic rock characterized by low quartz to feldspar ratio (±1 free quartz to 1-4 free feldspars). The studied placer feldspars were found to have good grinding ability that more than 75% of the charge were found over than 300 µm and less than 500 µm., the dust is less than 0.5%. These results are the required grain size with a release of both Na+ and k+ in the solution which, in turn, enhance the rheological properties of the ceramic slip. The results of the physical tests illustrated by water absorption %, shrinkage and bending strength beside their good resist for thermal shock and crazing suggest that the feldspars of the studied area can be used for only wall ceramic industry due to their high content of water absorption %, shrinkage and bending strength beside their good resist for thermal shock and crazing suggest that the feldspars of the studied area can be used for only wall ceramic industry due to their high content of water absorption%.