Element with atomic number 79, symbol Au, atomic weight 196.96, mp 1063°C, specific gravity 18.88. Native gold usually contains some copper and silver. Typical gold concentrations are 85% to 95% with the remainder being mostly silver. Gold is bright yellow, but with increasing silver content the colour is white, while copper provides red tints to the colour. With a platinum content of between 20 and 25% and nickel gold alloys become white.