Silicon is rarely found in nature in its uncombined form. In silicon is with 25.7% of the earth crust being silicon. Silicon, binds strongly with oxygen and is nearly always found as silicon dioxide (quartz) , so it the most second available material on earth and due to that the quartz crystal is (piezoelectric) so used in industry Ground silica, also known as ground quartz and silica flour, is produced by grinding high-purity quartz, quartzite, sandstone, or silica sand to finer than 200 mesh. Air separation is used as required to remove kaolin, mica, feldspar, or calcite impurities. Silica sand recovered as a byproduct during the flotation of other minerals is also used as a source. Ground silica for filler uses typically assays >99% sio2 and offers high brightness, low moisture, chemical inertness, relatively low surface area, and the low liquid absorption