Gold alloys will oxidize after annealing or soldering due to the other metals present. Even common chlorinated pool water can cause a loss of metal with prolonged exposure. Coloured Gold Coloured golds are produced by alloying other metals that impart their colour characteristics to gold. For example, white gold is alloyed by using white metals to give it a distinct colour. Green gold is also used.
Purple gold is made by alloying aluminum with fine gold.
Purple gold is very hard to work with and wears very poorly, but is sometimes used as inlays for jewellery. Gold Filled Gold filled jewellery consist of a base metal with a layer of gold clad to its surface. The advantage of gold filled over plating is the thickness of the surface gold. Silver Fine silver, meaning pure, is the whitest of all metals, has the greatest luster and is second only to gold for malleability and utility. Fine silver is also identified as 999 parts per thousand.