Silicon is the second most abundant element is the crust, after Oxygen.
Silicate minerals in the crust include those in the pyroxene, amphibole, mica, and feldspar group. These minerals occur in clay and various types of rock such as granite and sandstone.
Silica occurs in mineral consisting of very pure silicon dioxide, such as: Quartz, Agate, Amethyst, Rock Crystal, Chalcedony, Flint, Jasper, and Opal.
It is a tetravalent metalloid, more reactive than germanium.
Like water, it has a greater density in a liquid state than is a solid state. It does not contract when it freezes but expands.
Like Germanium, Silicon is rather strong, very brittle, and prone to chipping.
Silicon, like Carbon and Germanium, crystallizes in a diamond cubic crystal structure.
Silicon is a semiconductor. It has a negative temperature co-efficient of resistance, since the number of free charge carriers increases with temperature.
