Gold Content in Watches
Part 3 of 4

by Watchking

Yellow Gold

The most popular forms of 18 karat gold are both yellow. One form of popular 18 karat yellow gold is light yellow in color and it has the psychological advantage of looking like what people think pure gold should look like. Although this form of yellow gold is much "whiter" than real 24 karat gold, it is people's perceptions that shape their buying. For many years brass objects were gold plated to reduce oxidation and improve the surface sheen. This type of plated material looked very orange, almost like real 24 karat gold. This color of gold developed an image of being "cheap" and tacky. Lower karat forms of "pure" gold had a high silver content but consumers perceived the solid low karat gold color to be superior because this material was solid and the color went through and through as well as never tarnishing or oxidizing. The light yellow form of 18 kart gold has a metal content with 75% gold, 16% silver and 9% copper.

The disadvantage of this type of yellow gold is that it's silver content is the highest of all 18 karat gold. This high silver content makes it very soft and scratchable and more likely to trigger a poisonous reaction in some people. Light yellow 18 karat gold is also the densest form of 18 karat gold and so if weight is a factor this is the preferred alloy. The biggest problem that occurs in watch cases using this type of gold involves bent or cut lugs. Metal watch bracelets and spring bars can rip this form of gold and lugs will bend very easily. If the public's perception wasn't so firmly entrenched in favor of this color of gold, it would have few physical characteristics that would make it the most popular color. This color of gold is so dominant in the wedding band industry, that it is the most readily available form of 18 karat gold now and it will continue to be so for many years to come.  

The second form of yellow 18 karat gold is very popular because it really does look more like 24 karat gold than any other form. This type of gold alloy is made up of 75% gold, 12.5% silver and 12.5% copper. This type of yellow gold scratches less easily than the light colored form of yellow gold and it is more orange in color. This is the second most common form of 18 karat gold although 18 karat white gold is fast approaching it in popularity. This form of yellow gold is the second most dense and yet it is measurably harder than the other form of yellow gold because of the hardness added by copper. This means that if a watch case is made to be water resistant or exceptionally thin the darker and more orange form of yellow gold will be better because of its greater structural integrity. We forget that case hardened copper can be made so hard that battle swords were made from it 5,000 years ago. Buyers of high-end watch brands often prefer the darker form of yellow 18 karat gold also because they know it more closely resembles the color of 23 karat gold coins. This means that watch cases made from the darker color of yellow gold will last longer than the lighter colored alloy. In any case, yellow gold so totally dominates the market that this color in total is twice as popular as all the other forms combined in terms of total market share.  

There have been experiments in the production of other colors of gold but there seems to be almost no market for blue or violet color gold although there are some rare earth metal forms of violet gold that are available in Black Hills Gold products. In the industrial market there are some unusual forms of 18 karat gold alloys that have found their way into the watch case market. 18 karat gold that has a very high percentage of titanium is by far the hardest gold alloy form available. It's color is rather dark compared to most other forms of yellow 18 karat gold. Titanium is not considered a precious metal and silver is.

Making gold alloys with non-precious metals is common since copper is almost always used in gold alloys, but this is because copper is in the gold family and mixes well itself with gold as well as allowing other metals to mix well with gold. Titanium adds a "light' feel to gold that can be disconcerting to consumers. It's 18 karat alloy is thus used most commonly as a form of 18 karat gold plating. It adheres well to most metals and is remarkably scratch resistant. Unfortunately 18 karat gold made with titanium as a doping material does not polish well, requiring special diamond grits and long periods of buffing because of the alloy's hardness. This processing consideration also has discouraged the watch case makers from using it too often.

NOTE: Base Metal Content percentages may vary
slightly with each manufacturer.

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