Claim: Gold is resistant to all acids except aqua regia.

Gold is a chemical element with symbol Au -LRB- from aurum -RRB- and atomic number 79 . In its purest form , it is a bright , slightly reddish yellow , dense , soft , malleable , and ductile metal . Chemically , gold is a transition metal and a group 11 element . It is one of the least reactive chemical elements and is solid under standard conditions . Gold often occurs in free elemental -LRB- native -RRB- form , as nuggets or grains , in rocks , in veins , and in alluvial deposits . It occurs in a solid solution series with the native element silver -LRB- as electrum -RRB- and also naturally alloyed with copper and palladium . Less commonly , it occurs in minerals as gold compounds , often with tellurium -LRB- gold tellurides -RRB- .   Gold 's atomic number of 79 makes it one of the higher numbered , naturally occurring elements . It is thought to have been produced in supernova nucleosynthesis , from the collision of neutron stars , and to have been present in the dust from which the Solar System formed . Because the Earth was molten when it was formed , almost all of the gold present in the early Earth probably sank into the planetary core . Therefore , most of the gold that is present today in the Earth 's crust and mantle is thought to have been delivered to Earth later , by asteroid impacts during the Late Heavy Bombardment , about 4 billion years ago .   Gold is resistant to most acids , though it does dissolve in aqua regia , a mixture of nitric acid and hydrochloric acid , which forms a soluble tetrachloroaurate anion . Gold is insoluble in nitric acid , which dissolves silver and base metals , a property that has long been used to refine gold and to confirm the presence of gold in metallic objects , giving rise to the term acid test . Gold also dissolves in alkaline solutions of cyanide , which are used in mining and electroplating . Gold dissolves in mercury , forming amalgam alloys , but this is not a chemical reaction .   Historically , the value of gold was rooted in its relative rarity , easy handling and minting , easy smelting and fabrication , resistance to corrosion and other chemical reactions -LRB- nobility -RRB- and its distinctive color . As a precious metal , gold has been used for coinage , jewelry , and other arts throughout recorded history . In the past , a gold standard was often implemented as a monetary policy , but gold coins ceased to be minted as a circulating currency in the 1930s , and the world gold standard was abandoned for a fiat currency system after 1976 .   A total of 186,700 tonnes of gold is in existence above ground , as of 2015 . The world consumption of new gold produced is about 50 % in jewelry , 40 % in investments , and 10 % in industry . Gold 's high malleability , ductility , resistance to corrosion and most other chemical reactions , and conductivity of electricity have led to its continued use in corrosion resistant electrical connectors in all types of computerized devices -LRB- its chief industrial use -RRB- . Gold is also used in infrared shielding , colored-glass production , gold leafing , and tooth restoration . Certain gold salts are still used as anti-inflammatories in medicine . As of 2014 , the world 's largest gold producer by far was China with 450 tonnes .