silica

n. silicon dioxide, crystalline compound commonly found in sand and quartz (used to produce glass, cement, ceramic, and other products)

Silica redirects here. For other uses, see Silica (disambiguation) The chemical compound silicon dioxide, also known as silica or silox (from the Latin "silex"), is the oxide of silicon, chemical formula O, and has been known for its hardness since the 16th century. It is a principal component of most types of glass and substances such as concrete.Siliceous is an adjective meaning "related to silica".
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n. silica, crystalline compound commonly found in sand and quartz

(n.)
Silicon dioxide, SiO/. It constitutes ordinary quartz (also opal and tridymite), and is artifically prepared as a very fine, white, tasteless, inodorous powder.
  

Silicon dioxide (SiO2). Note 1: Silica may occur in crystalline or amorphous form, and occurs naturally in impure forms such as quartz and sand. Note 2: Silica is the basic material of which the most common communication-grade optical fibers are presently made. [After FAA]