Gold is a chemical element with the symbol Au and atomic number 79, making it one of the highest atomic number elements that occur naturally. 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 form, as nuggets or grains, in rocks, in veins, and in alluvial deposits.