Aqua regia (Latin, lit. "royal water" or "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. Aqua regia was so named because it can dissolve the noble metals gold and platinum. However, titanium, iridium, ruthenium, rhenium, tantalum, niobium, hafnium, osmium and rhodium are capable of withstanding its corrosive properties.