A silicate is a compound containing an anionic silicon compound. The great majority of silicates are oxides, but hexafluorosilicate ([SiF 6 ] 2−) and other anions are also included.
Silicates. The most abundant elements in the Earth's crust are oxygen (46.6%) and silicon (27.7%). Minerals which combine these two elements are called silicates, and combined they are the most abundant minerals on the Earth. The silicates can be organized in terms of their chemical compositions and their crystal structures (indicated by the existance of cleavage planes The silicates are the largest, the most interesting and the most complicated class of minerals than any other minerals. Approximately 30% of all minerals are silicates and some geologists estimate that 90% of the Earth's crust is made up of silicates, SiO. Silicates is based on the basic chemical unit SiO. In the extreme case, the tetrahedra are arranged in a regular, orderly fashion forming a three-dimensional network. A silicate is a compound containing an anionic silicon compound. The great majority of silicates are oxides, but hexafluorosilicate ([SiF 6 ] 2−) and other anions are also included.  Orthosilicate  is the anion SiO 4 4− or its compounds. Related to orthosilicate are families of anions (and their compounds) with the formula [SiO 2+n ] 2n− . Silicates are by far the most common minerals in Earth's crust and mantle, making up 95% of the crust and 97% of the mantle, by most estimates. Silicates have a wide variety of physical properties, despite the fact that they often have very similar chemical formulas.  Building Blocks of The Earth’s Crust. Silicates are the most widespread of the minerals. They are made up of oxygen and silicon the number one and number two most abundant elements in the earth's crust. By themselves they make up over 90% of the weight of the earth’s crust. Most rocks are composed mainly of this class of minerals The silicate minerals are rock-forming minerals, constituting approximately 90 percent of the crust of the Earth. They are classified based on the structure of their silicate group which contain different ratios of silicon and oxygen. They make up the largest and most important class of rock-forming minerals. The Silicates are the largest, the most interesting, and the most complicated class of minerals by far. Approximately 30% of all minerals are silicates and some geologists estimate that 90% of the Earth's crust is made up of silicates. With oxygen and silicon the two most abundant elements in the earth's crust, the abundance of silicates is no real surprise. A. Non-silicates 1. Non-silicates are minerals other than silicate minerals 2. Less complex than silicates 3. Economically important B. Ore Mineral 1. Minerals that can be profitably extracted 2. Often contain impurities C. Impurities 1. Do not constitute part of the mineral formula 2. Are always present 3. Silicates comprise the majority of Earth's crust, as well as the other terrestrial planets, rocky moons, and asteroids. Sand, Portland cement, and thousands of minerals are examples of silicates. Silicate compounds, including the minerals, consist of silicate anions whose charge is balanced by various cations. Myriad silicate anions can exist, and each can form compounds with many different cations. The great majority of silicates are oxides, but hexafluorosilicate ([SiF 6 ] 2−) and other anions are also included.  Orthosilicate  is the anion SiO 4 4− or its compounds. Related to orthosilicate are families of anions (and their compounds) with the formula [SiO 2+n ] 2n− .
http://hyperphysics.phy-astr.gsu.edu/hbase/geophys/silicate.html http://www.science.uwaterloo.ca/~cchieh/cact/applychem/silicate.html https://en.wikipedia.org/wiki/Silicate http://www.visionlearning.com/en/library/Earth-Science/6/The-Silicate-Minerals/140 http://www.rocksandminerals4u.com/silicates.html https://en.wikipedia.org/wiki/Silicate_minerals http://www.galleries.com/Silicates http://www.auburn.edu/academic/classes/geol/0110/Non-silicates.html https://en.wikipedia.org/wiki/Silicate
what are silicates