Silicon is prepared by heating silicon dioxide with carbon. Carbon replaces the silicon in the compound.
Silicon is a metalloid, an element with properties of both metals and non-metals. Silicon exists in two allotropic forms. Allotropes are forms of an element with different physical and chemical properties. One allotrope is in the form of shiny, grayish-black, needle-like crystals, or flat plates. The second allotrope has no crystal structure and usually occurs as a brown powder.