Gold is a chemical element with atomic number 79. Its symbol is Au (from the Latin "aurum"). This transition metal is soft, heavy, ductile, malleable and yellow in colour due to the absorption of blue wavelengths from incident light.
Impervious to most chemical compounds, it reacts in practice only with aqua regia and cyanide ion. In contact with mercury, it forms an amalgam but not a chemical compound. It is found in its natural state in the form of nuggets, grains and flakes in rocks and alluvial deposits.
We use it for the manufacture of products in the field of jewellery and in the medical and industrial sectors in general.