Legend Group 11, by modern IUPAC numbering,[1] is a group of chemical elements in the periodic table, consisting of copper (Cu), silver (Ag), gold (Au), and roentgenium (Rg), although no chemical experiments have yet been carried out to confirm that roentgenium behaves like the heavier homologue to gold.

[4][5] All three stable elements of the group have been known since prehistoric times,[2] as all of them occur in metallic form in nature and no extraction metallurgy is necessary to produce them.

The first evidence of silver mining dates back to 3000 BC, in Turkey and Greece, according to the RSC.

The earliest recorded metal employed by humans appears to be gold, which can be found free or "native".

Small amounts of natural gold have been found in Spanish caves used during the late Paleolithic period, c. 40,000 BC.

Copper occurs in its native form in Chile, China, Mexico, Russia and the USA.

Silver is found in native form, as an alloy with gold (electrum), and in ores containing sulfur, arsenic, antimony or chlorine.

These metals, especially silver, have unusual properties that make them essential for industrial applications outside of their monetary or decorative value.

Gold, silver, and copper are quite soft metals and so are easily damaged in daily use as coins.

Wilson's disease is a genetic condition in which a protein important for excretion of excess copper is mutated such that copper builds up in body tissues, causing symptoms including vomiting, weakness, tremors, anxiety, and muscle stiffness.

The prolonged use of preparations containing gold or silver can also lead to the accumulation of these metals in body tissue; the results of which are irreversible but apparently harmless pigmentation conditions known as chrysiasis and argyria respectively.