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Gold ( /ˈɡoʊld/) is a chemical element with the symbol Au (from Latin: aurum “gold”) and an atomic number of 79. Gold is a dense, soft, shiny metal and the most malleable and ductile metal known. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a transition metal and a group 11 element. With exception of the noble gases, gold is the least reactive chemical element known. It has been a valuable and highly sought-after precious metal for coinage, jewelry, and other arts since long before the beginning of recorded history.Gold resists attacks by individual acids, but it can be dissolved by the aqua regia, so named because it dissolves gold. Gold also dissolves in alkaline solutions of cyanide, which have been used in mining. Gold dissolves in mercury, forming amalgam alloys. Gold is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to confirm the presence of gold in items.The native metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Less commonly, it occurs in minerals as gold compounds, usually with tellurium. Gold standards have been the most common basis for monetary policies throughout human history, being widely supplanted by fiat currency only in the late 20th century. Gold has also been frequently linked to a wide variety of symbolisms and ideologies. A total of 165,000 tonnes of gold have been mined in human history, as of 2009.[1] This is roughly equivalent to 5.3 billion troy ounces or, in terms of volume, about 8,500 m³, or a cube 20.4 m on a side. The world consumption of new gold produced is about 50% in jewelry, 40% in investments, and 10% in industry.[citation needed]Besides its widespread monetary and symbolic functions, gold has many practical uses in dentistry, electronics, and other fields. Its high malleability, ductility, resistance to corrosion and most other chemical reactions, and conductivity of electricity lead to many uses of gold, including electric wiring, colored glass production and even gold leaf eating.