Panerai Radiomir 10 Days GMT Osaka Boutique (PAM00589)

When it comes to gold watches, not all golds are the same. Beyond the simple differences in yellow, red and white gold, brands are increasingly differentiating their collections with their own personalized alloys of the precious metal.

For many, a Swiss Made gold watch is the ultimate status symbol, regardless of the complexity of the movement that beats inside it. But the sheer range of different types of gold offered by luxury watch brands, each clamouring to ensure us that their version of gold is better than anyone else's, can be confusing.

How gold is your gold?
It's interesting to note that the ISO 8654 standard that governs the colours of gold is actually derived from a Swiss watchmaking industry standard that was first drawn up in 1966. This standard classifies gold colours in six grades, from 0N to 5N, the latter of which you may well have seen in numerous gold watch specifications. But what do these numbers mean?

They refer to the observed colour of the finished product, rather than any specific alloy of gold. The 0N and 1N colours contain only 58.5% gold and are therefore not 18-carat (or 18K or 18 Karat if you are American) alloys. Any alloy containing 75% gold or above is considered 18-carat, which is the case for 2N to 5N gold. At the top of the scale, 5N gold contains the least amount of silver if it is used in the alloy and therefore offers the reddest hue to the finished product, which is referred to as red, pink or rose gold, depending on the watch brand.

The World Gold Council, however, uses a much more specific notation, subdivided into three colours of 18-carat gold as follows:

• Yellow gold: 75% gold, 15% silver, 10% copper
• White gold: 75% gold, 25% platinum or palladium
• Rose gold: 75% gold, 9.2% silver, 22.2% copper

As we can see from the current offerings from the leading watch brands, not all rose gold alloys - the predominant one at least as far as men's gold watches are concerned - are the same, as the brands carefully juggle the three main constituents of the alloy to create their own "house blends".

Magic Gold - Hublot
Hublot's unique and proprietary Magic Gold alloy is produced in the brand's own mini-foundry on site at the manufacture in Nyon. The secret recipe combining gold, copper and platinum creates the world's first and only scratch-proof 18-carat gold alloy.

Sedna Gold - Harry Winston
First used by Omega, this gold alloy that is exclusive to the Swatch Group brands contains a higher proportion of palladium, which gives the case a warmer colour and finish. Harry Winston uses it for the first time this year in its Avenue collection. The palladium ensures a long-lasting lustre to the red tones in the case. The alloy is named after the trans-Neptunian object that astronomers called Sedna and is renowned for its red glow.

King Gold - Hublot
King Gold is the other gold alloy used by Hublot. Its exclusive colour is even redder than traditional 5N red gold. To achieve this result, the brand's metallurgists increased the percentage of copper and added platinum in order to stabilise the colour over the years and neutralise oxidation.

5Npt gold - Panerai
Surprisingly, Panerai only introduced its first models in red gold at the SIHH in 2012. The 5Npt alloy used by the Florentine brand consists of almost one-quarter (24.1%) copper, which adds a redder tinge to the gold Panerai watches. Like Hublot, Panerai adds a tiny percentage of platinum (0.4%) to prevent oxidation of the metal.

Chopard - Fairmined gold
Chopard cares more about the provenance of its gold than it does about its colour. The brand has gone to great lengths to incorporate Fairmined gold into its collection, since it requires an entirely separate foundry and production line and it must ensure that the Fairmined gold is not contaminated with any other type of gold - even in the waste recovered during the manufacturing process. The Fairmined appellation means that the gold was mined in a responsible manner and that the miners themselves receive fair payment and an overall premium for demonstrating that gold can be mined sustainably.
Chopard was the first brand to launch a high-end luxury watch made of Fairmined gold: the L.U.C Tourbillon QF Fairmined, which was presented at Baselworld last year.