" In mineralogical chemistry the silicates include; the unisilicates or orthosilicates, salts of orthosilicic acid; the bisilicates or metasilicates, salts of metasilicic acid; the polysilicates or acid silicates, salts of the polysilicic acids; the basic silicates or subsilicates, in which the equivalent of base is greater than would be required to neutralize the acid; and the hydrous silicates, including the zeolites and many hydrated decomposition products." [1913 Webster]

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OXFORD DICTIONARY

silicate, n. any of the many insoluble compounds of a metal combined with silicon and oxygen, occurring widely in the rocks of the earth's crust.

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