What is "Aqua regiaor"?
water with the addition of a small amount of gold
the mythic substance that the alchemists wanted
Aqua regiaor ("king's water") is a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3. Aqua regia is a yellow-orange fuming liquid, so named by alchemists because it can dissolve the noble metals gold and platinum, though not all metals.