Silicon is
rarely found in nature in its uncombined form. In silicon is
with *5.7% of the Earths 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 **0 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 >*9% SiO2
and offers high brightness, low moisture, chemical inertness,
relatively low surface area, and the low liquid
absorption
