sharp as razor blades.
Other materials used by hominids are clay and glass, both of which
contain silicon compounds. Clay is made up of a collection of silicates and
was learned to be used for both pottery and construction. There is still not
enough information on how glass technology was discovered or began to be
used, but from archaeological finds, it was probably in Asia Minor before
12000 BC. By 1787 it was assumed that silica was an element; but, in the
same year Lavoisier suggested that this material was an oxide of some other
unknown element. Gay Lussac and Thénard were apparently the first to
produce silicon in 1811 by reduction of silicon fluoride with potassium; but
this is not recognized as the discovery. Berzelius in 1817 reports evidence
of a new element as a precipitate in an iron vessel. In 1823 he obtained it by
reacting potassium fluorosilicate with potassium metal, and by washing the
product with water he obtained a greyish powder which was amorphous
silicon. It was not until 1854 that silicon was obtained repeatedly by
Sainte-Claire Deville, who crystallized this element from electrolysis of
mixtures with chlorinated substances. This process was the origin of two
variants of amorphous silicon (^) [ 88 ].