Watch 101: Understanding The Different Types Of Gold In Watchmaking
Gold, in its natural form, is soft, dense and inert. It also has a yellow sheen that is rather garish by today’s discreet luxury standards. In the watch industry, gold is often mixed with other metals to make it stronger and more resistant, creating what is called gold alloys. The mixture also changes the colour of gold; depending on the types of metal, it ranges from red gold to brilliant white.
The measurement for the purity of gold is karat. An 18k gold, for instance, is composed of 75% gold and 25% other metals. A gold that is certified 24k is pure gold without any additional metal. However, note that the higher the karat, the less hardy the gold is, and vice versa.
In general, Swiss manufactures never go lower than 18k gold, which is also the point when gold can start to adopt different colours. In a bid to boost their stature, some manufactures like Hublot have even gone as far as innovating and patenting their own gold.
Red Gold/ Rose Gold/ Pink Gold
Red gold is essentially composed of gold and copper. The amount of copper used dictates the colour intensity. Although the term is sometimes used interchangeably with rose or pink gold, the latter actually has a hint of zinc for a more subdued tone of red. If you’re wine lover, it is the difference between a rosé and a red wine
This colour is achieved by mixing gold with other white metals. In fine watchmaking, that metal is often palladium, a close cousin of platinum. It is usually coated with rhodium to achieve the desired brilliance, as white gold alloy looks dull and grey.
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Ceragold and Sedna Gold
Ceragold is ceramic with a golden shine. Created by Omega originally for the bezel of the Seamaster Planet Ocean dive watch, rings of ceramic made of zirconium oxide are plunged into an electric 18k gold bath, and remain there for 48 hours. Excess gold is removed to recover the black ceramic surface, leaving only solid gold for the diving scale. The circularly brushed gold makes for a striking contrast against the polished ceramic, but the entire surface is absolutely smooth to the touch.
Another trademarked gold creation by Omega is Sedna gold, which has appeared in its Constellaton watch. The gold alloy is composed of a certain percentage of copper and palladium for a unique rose gold lustre that promises to last for a long time.
Magic Gold and King Gold
With Hublot's Art of Fusion philosophy in mind , gold offers the manufacture a fantastic canvas to mix things up. In the case of Magic Gold, it was hailed as the first 18k gold to be completely scratch-resistant. Created at Hublot's foundry in Nyon, the gold is achieved by injecting boron carbide (one of the materials for making ceramic) with 24k gold alloyed with 3% molten liquid gold. Hublot claims that Magic Gold is so tough that only a diamond can scratch it!
While Magic Gold has an industrial-looking yellow sheen, King Gold boasts a more fiery tone than the standard 18k 5N red gold, the result of increasing the percentage of copper from the usual 20.5%. On top of that, it adds platinum to the mix to stabilise the colour in the long run.
One of the best looking rose gold comes from Rolex. The brand-exclusive Everose gold has a luxurious pinkish hue formed from pure gold combined with a secret percentage of copper that gives it its unique warm colour. A hint of platinum is added to ensure that the pink doesn’t lose its lustre in years to come.