White gold is an alloy of gold and at least one white metal, usually nickel, manganese or palladium. Like yellow gold, the purity of white gold is given in karats.
White gold's properties vary depending on the metals and proportions used. As a result, white gold alloys can be used for many different purposes; while a nickel alloy is hard and strong and therefore good for rings and pins, gold-palladium alloys are soft, pliable and good for white gold gemstone settings, sometimes with other metals like copper, silver, and platinum for weight and durability, although this often requires specialized goldsmiths. The term white gold is used very loosely in the industry to describe karat gold alloys with a whitish hue. Many believe that the color of the rhodium plating, which is seen on many commercial pieces, is actually the color of white gold. The term "white" covers a large spectrum of colors that borders or overlaps pale yellow, tinted brown, and even very pale rose. The jewelry industry often improves these off-white colors by rhodium plating.
A common white gold formulation consists of 90 wt.% gold and 10 wt.% nickel. Copper can be added to increase malleability.
The strength of gold-nickel-copper alloys is caused by formation of two phases, a gold-rich Au-Cu, and a nickel-rich Ni-Cu, and the resulting hardening of the material.
The alloys used in jewelry industry are gold-palladium-silver and gold-nickel-copper-zinc. Palladium and nickel act as primary bleaching agents for gold; zinc acts as a secondary bleaching agent to attenuate the color of copper.
Read more about this topic: Red Gold
Famous quotes containing the words white and/or gold:
“Almost like a god looking at her terribly out of the everlasting dark, she had felt the eyes of that horse; great glowing, fearsome eyes, arched with a question, and containing a white blade of light like a threat. What was his non-human question, and his uncanny threat? She didn’t know. He was some splendid demon, and she must worship him.”
—D.H. (David Herbert)
“‘She has got rings on every finger,
Round one of them she have got three.
She have gold enough around her middle
To buy Northumberland that belongs to thee.”
—Unknown. Young Beichan (l. 61–64)