1. Silicon is a chemical element with symbol Si and atomic number 14. A hard and brittle crystalline solid with a blue-gray metallic luster, it is a tetravalent metalloid. It is a member of group 14 in the periodic table, along with carbon above it and germanium, tin, lead, and flerovium below. It is not very reactive, although more reactive than carbon, and has great chemical affinity for oxygen; it was first purified and characterized in 1823 by Jöns Jakob Berzelius. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is most widely distributed in dusts, sands, planetoids, and planets as various forms of silicon dioxide (silica) or silicates.
2. The metalloid silicon is a very abundant element. Much of the earth's crust is made out of silicates and silica (SiO2). The latter is the chief ingredient of quartz and sand and is used as raw material for glass since ages. Elemental silicon is an important industrial material, where it is used in huge amounts for semiconductors, computer chips, in electronics, for solar energy and photovoltaics.
Amorphous silicon, Monocrystalline Silicon
https://en.wikipedia.org/wiki/Silicon (1.); http://images-of-elements.com/silicon.php (2.)
Author: Svenja Gutt