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A group of minerals containing various amounts of the elements Silicon and Oxygen. The Silicates are the largest group of minerals. The construction component of all Silicates is the tetrahedron, which is one Silicon atom equidimensionally placed around four Oxygen atoms.
Almost 85% of the atoms in the crust are oxygen or silicon atoms, and as a result the vast majority of common (rock-forming) minerals are silicates -- combinations of oxygen and silicon primarily with the other six (most common) metals listed above. Pure silica or quartz consists of only silicon and oxygen.