Looking Ahead - Mining and the Environment: From Ore to Metal - page 831

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Looking Ahead

SILICON

Silicon, a brittle, gray metalloid, is the most abundant metal and the second most
abundant element in the Earth's crust. Relatively unreactive, it occurs in nature as
the oxide form, silica, of which quartz is the most common mineral, and in numerous
silicate minerals which include many of the most common constituents of igneous
and metamorphic rocks. Silicon is essential to many living organisms, particularly
plants and many marine invertebrates. It is not toxic to humans. The majority of
silicon is used in specialized alloys. However, the most important applications are
in electronics where silicon is used in transistors, computer chips and photovoltaic
cells. Silica is used to make glass, cement and refractory materials. Silicon metal
is produced from high purity silica in an electric arc furnace.