Jewellery is usually made of precious metals, because these materials combine properties that are expected of high-quality and attractive jewellery. As a result, precious metals also have a high material value, which is of course also in the focus of exclusive jewellery. Precious metals include those metals that have a special resistance to corrosion. Silver and gold are the best-known representatives of the group of precious metals. Because of its resistance to corrosion, precious metal has been a sought-after material for jewellery for many thousands of years, but it has also been used for coins throughout the ages. Precious metals do not rust, or at least only to an extremely low and slow degree. Most acids also do not attack precious metals. Besides gold and silver, platinum, iridium, palladium, osmium, mercury (more reactive than other precious metals), rhodium and ruthenium are among the classic precious metals that have also gained their fame through their use as jewellery material. For jewellery, lasting durability is of course of greatest interest, as this is the only way to ensure a lifetime of value retention. The base metals, of which lead, aluminium or iron are the best known, are clearly to be distinguished from the precious metals.
