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The '''silicates''' are the largest and the most complicated class of minerals. Approximately 30% of all minerals are silicates and geologists estimate that 90% of the crust of the Earth is made up of silicates. This is so since oxygen and silicon are the two most abundant elements in the Earth's crust.

The '''silicates''' are the largest and the most complicated class of minerals. Approximately 30% of all minerals are silicates and geologists estimate that 90% of the crust of the Earth is made up of silicates. This is so since [[oxygen]] and [[silicon]] are the two most abundant elements in the Earth's crust.

The basic chemical unit of silicates is the (SiO₄) tetrahedron shaped anionic group with a negative four charge (-4). The central silicon ion has a charge of positive four while each oxygen has a charge of negative two (-2) and thus each silicon-oxygen bond is equal to one half (1/2) the total bond energy of oxygen. This condition leaves the oxygens with the option of bonding to another silicon ion and therefore linking one (SiO₄) tetrahedron to another and another, etcetera.<ref>[http://www.galleries.com/minerals/silicate/class.htm]</ref>

The basic chemical unit of silicates is the (SiO₄) tetrahedron shaped anionic group with a negative four charge (-4). The central silicon ion has a charge of positive four while each oxygen has a charge of negative two (-2) and thus each silicon-oxygen bond is equal to one half (1/2) the total bond energy of oxygen. This condition leaves the oxygens with the option of bonding to another silicon ion and therefore linking one (SiO₄) tetrahedron to another and another, etcetera.<ref>[http://www.galleries.com/minerals/silicate/class.htm]</ref>