Gold October 10 2014
Pure gold is yellow in color, but colored gold in various other colors can be produced.
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[who?] 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.
Rose gold is a gold and copper alloy widely used for specialized jewelry. Rose gold, also known as pink gold and red gold, was popular in Russia at the beginning of the nineteenth century, and was also known as Russian gold, although this term is now obsolete. Rose gold jewelry is becoming more popular in the 21st century and is commonly used for wedding rings, bracelets, and other jewelry.
Although the names are often used interchangeably, the difference between red, rose, and pink gold is the copper content – the higher the copper content, the stronger the red coloration. Pink gold uses the least amount of copper content, followed by rose gold, and red gold has the highest copper content.