What is Silicon dioxide?
'''Silicon dioxide''', also known as '''silica''', is a [[chemical compound]], the [[oxide]] of [[silicon]]. Its chemical symbol is SiO<sub>2</sub>. It is known for its hardness since the 16th century. It has an important compound used in most types of [[glass]] and other hard substances such as [[concrete]], [[porcelain]] and [[stoneware]]. It is made up of 2 oxygen atoms and 1 silicon atom. Silicon dioxide exists in [[nature]] in a number of forms, including [[flint]], [[quartz]] and [[opal]]. If it is breathed in as [[dust]], it can cause [[silicosis]] and [[cancer]], as the dust is trapped in the [[lung]]s. Besides the dangers of inhaling it in dust form, it is harmless. {{chem-stub}} [[Category:Chemical compounds]] [[Category:Oxides]]