What does 18K gold mean for a watch, and what is the symbol of an 18K gold watch?

What does 18K gold mean for a watch?

As we all know, gold is soft in texture. Although this metal can be made into watch cases and buckles, it is easily damaged. Therefore, nowadays, except for some brands that use pure gold for gimmicky purposes, almost all brands adopt alloy materials with gold as the main component. Among such alloy materials, the most popular one is a mixture of 75% gold and 25% other metals. This proportion of alloy material is called “750” or “18K”. These two numbers indicate that the proportion of gold in the alloy is 750 per thousand, or 18 out of 24.

For watches made of 18K yellow gold, 18K red gold, or 18K white gold, the usual hallmarks are “750” or “18K”. Platinum is an exception, which is marked as “PT950”. Here, “PT” is the abbreviation of “Platinum”, and “950” refers to its purity.

The mixture of 75% gold will have different colors and hardness depending on the types and proportions of other metals added.

18K white gold: The other 25% of metals in 18K white gold are generally nickel, silver, manganese, etc. The addition of these metals can turn the color of gold into white.

18K rose gold: The color of 18K rose gold mainly comes from copper and a small amount of silver. Each brand has a different mixing ratio formula, so the colors of rose gold watches we see are different. When the copper content increases, the overall color tends to be more red; when the silver content increases, the overall color is closer to the natural color of 18K yellow gold.

The color of rose gold is not very stable; it may fade after long-term wear or natural oxidation. To make the color more stable, a very small amount of inert metal is usually added as a stabilizer during the fusion process. For example, Rolex’s 18K gold contains a small amount of platinum to ensure the color remains durable and uniform. The unique formula has become a secret of each independent brand, which also makes the 18K rose gold of each brand present a different color.

What is the hallmark of an 18K gold watch?

There are four essential hallmarks on modern Swiss precious metal watch cases: the Saint Bernard dog’s head (or the Queen’s head), the material balance mark, the fineness mark, and the manufacturer’s responsibility mark or trademark.

When Switzerland revised its regulations on precious metal hallmarks in 1995, it stipulated that the profile of the national dog, the Saint Bernard, should be used as the sole mark for precious metal products made in Switzerland. In Switzerland, the Saint Bernard’s head is currently the only precious metal hallmark, and the Saint Bernard’s head hallmark is a legally protected exclusive mark.

Like the dog’s head, the balance is also a unique precious metal hallmark, but it is often overlooked. The shape of the balance is not as complex as that of the dog’s head or the Queen’s head, and its versions are relatively uniform. Therefore, observing the shape of the balance can sometimes become an important skill in identifying precious metal hallmarks.