White bronze is actually not bronze. It is an alloy consisting of a combination of copper, tin, and zinc and is also known as ‘Miralloy’. Due to nickel now being banned for jewellery use in the EU white bronze is considered the preferred, practical and safe alternative to nickel for items that can come into contact with the skin such as jewellery, buttons and zips, to name a few. Staggeringly, 15% of the US population has an allergic reaction to nickel as opposed to only 10% in the 80’s suggesting nickel related allergies appear to be on the rise. White bronze eliminates this problem which is why Pure Gold Plating now uses white bronze for all items likely to come into contact with the skin.
Because of its appearance and chemical properties white bronze is an ideal substitute for nickel and silver. Also, because white bronze is highly resistant to corrosion and breakdown, being solderable, non-magnetic, smooth, and virtually non-porous, it also has one advantage over silver, it will not tarnish.
There are certain situations when white bronze cannot be used as a substitute for silver, it is not used to replace silver in jewellery made only of silver because then it would not be silver. It is used as a barrier between a base metal and gold plating in gold plated jewellery. A perfect example would be gold plating a copper ring. White bronze would first be electroplated onto the copper before the gold to act as this barrier. Without this white bronze layer the copper atoms would diffuse into the gold layer and eventually affect the gold colour. This process can take anywhere from months to several years.
White bronze is actually very attractive, despite its low cost, meaning that in some jewellery it can be used as the final layer. White bronze usually has a thickness of about 1 to 2.5 microns when used internally as a barrier layer. One micron is only 1 – 1/1000th of 1mm.
Certain companies, from the late 1800s, were using white bronze for grave markers. Though, this type was mostly zinc (sold as “White Bronze”) giving the impression of a more luxurious and expensive metal, rather than the mainly tin alloy it was. Grave markers made of this material usually had a pale blue appearance due to the metal finishing process they underwent called “steam bluing”.