Gold is a chemical element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...

 with the symbol Au (from "gold") and an atomic number
Atomic number
In chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...

 of 79. Gold is a dense, soft, shiny, malleable and ductile metal. 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
Transition metal
The term transition metal has two possible meanings:*The IUPAC definition states that a transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." Group 12 elements are not transition metals in this definition.*Some...

 and a group 11 element
Group 11 element
A Group 11 element is one in the series of elements in group 11 in the periodic table, consisting of transition metals which are the traditional coinage metals of copper , silver , and gold...

. It is one of the least reactive solid chemical elements. The metal therefore occurs often in free elemental (native) form, as nuggets
Gold nugget
A gold nugget is a naturally occurring piece of native gold. Watercourses often concentrate and grow the nuggets. Nuggets are recovered by placer mining, but they are also found in residual deposits where the gold-bearing veins or lodes are weathered...

 or grains in rocks, in veins
Vein (geology)
In geology, a vein is a distinct sheetlike body of crystallized minerals within a rock. Veins form when mineral constituents carried by an aqueous solution within the rock mass are deposited through precipitation...

 and in alluvial deposits.

631    Emperor Taizong of Tang, the Emperor of China, sends envoys to the Xueyantuo bearing gold and silk in order to seek the release of enslaved Chinese prisoners captured during the transition from Sui to Tang from the northern frontier; this embassy succeeded in freeing 80,000 Chinese men and women who were then returned to China.

1539    In Florida, Hernando de Soto lands at Tampa Bay with 600 soldiers with the goal of finding gold.

1848    California Gold Rush: James W. Marshall finds gold at Sutter's Mill near Sacramento.

1848    California Gold Rush: In a message before the U.S. Congress, US President James K. Polk confirms that large amounts of gold had been discovered in California.

1849    The U.S. Congress passes the Gold Coinage Act allowing the minting of gold coins.

1864    Helena, Montana is founded after four prospectors discover gold at "Last Chance Gulch".

1869    "Black Friday": Gold prices plummet after Ulysses S. Grant orders the Treasury to sell large quantities of gold after Jay Gould and James Fisk plot to control the market.

1926    Gold is discovered in Johannesburg, South Africa.

1933    The U.S. Congress abrogates the United States' use of the gold standard by enacting a joint resolution (48 Stat. 112) nullifying the right of creditors to demand payment in gold.

1938    Archaeologists discover engraved gold and silver plates from King Darius in Persepolis.