A more practical method of making "gold chloride" is to add gold to aqua regia, a 1 : 3 molar ratio mix of concentrated nitric acid and hydrochloric acid.
The commercial material usually is not true gold chloride, AuCl3, but tetrachlorauric acid, HAuCl4.3H2O, which, when dissolved in water, gives H(+) ions and AuCl4(-) ions. The latter also is obtained, when gold metal is dissolved in aqua regia.