Apple’s patent-pending 18k gold: Harder, more scratch-resistant, and ‘less gold’

Apple’s patent application is for a method that allows them to make 18k gold that has, on a volume basis, less gold than regular 18k gold,” Dr. Drang blogs.

“How can this be? It’s because Apple’s gold is a metal matrix composite, not a standard alloy,” Dr. Drang explains. “Instead of mixing the gold with silver, copper, or other metals to make it harder, Apple is mixing it with low-density ceramic particles. The ceramic makes Apple’s gold harder and more scratch-resistant—which Tim Cook touted during the September announcement—and it also makes it less dense overall.”

“The karat measure of gold is based on the mass fraction. One hundred grams of 18k gold has 75 grams of gold and 25 grams of other material. If that ‘other material’ is a low-density ceramic, it takes up a bigger volume than if it’s a high-density metal. Because the casing of a watch is made to a particular size (i.e. volume), not to a particular weight, the Apple Watch will have less gold in it than an 18k case made of a conventional alloy,” Dr. Drang explains. “The patent makes it clear that saving gold is one of the goals of the process.”

More info and a bunch of math in the full article here.

Related articles:
Apple may buy 746 tons of gold per year for its Apple Watches – March 7, 2015


    1. Only in this case sold by volume, and not by weight. It is a good thing too, because if they sell as many as the projections currently show, if it had been by weight, Apple might well use up nearly a third of world annual gold production. It will be bad enough as it is. Who would have guessed that Apple could cause market disruption in not just music and phones but even the gold market?

    2. What’s the big deal. Gold watches aren
      t valued by their gold content., e.g., Rolex President contains less than 2 Troy ounces (watch and band) of 18 kt gold (by any measure).

      Two Troy ounces of 24 kt gold is worth about US$2,400. Yet the President sells for US$20,000.

      This is another, in a long list of articles, wherein the author is doing nothing but marketing his/her name.

      Frankly, if I were to buy a “gold” watch, I’d opt for harder and less vs more and softer.

  1. That’s pretty cool. So the metallic content is actually “pure” gold, though with less gold overall. This method will probably make recovery of gold from the case easier, since the other material is not metal. And it makes the gold Apple Watch functionally better, by making it lighter.

    1. However, there is no information yet that this patent has anything to do with the Watch — Apple did not mention ceramics in any of the presentations or descriptions of the material.

      Usual qualitative descriptions such as “twice harder” and the like are not indications since whole point of 18 karat golden alloy versus 24 karat (100%) gold is adding other materials that make whole thing significantly harder.

      But lets see; maybe Apple will give some indication of the material on Monday, or iFixit will weigh the body of golden Apple Watch (if they will have money to buy it. ;))) — then we will know with absolute certainty whether ceramics is used or not due to weigh/volume calculations.

      By the way, one importance consequence of use of such ceramics is noticeably lower weight of such golden alloy body — there is no need to make Watch too heavy.

  2. Wait for it, samsung will copy this process and many other and judge Lucy will allow that millions in investigation go to trash be use of her.. And the conformist.

  3. So it is a lower density material employing ceramic particles, but it is still 18k gold, or 75% gold by weight. Like any other gold object, it will have an intrinsic value based on its gold content – total weight multiplied by percentage of gold.

    The Apple watch is fairly large, so a lower density gold-based metal matrix composite makes a lot of sense to me. Few people want to wear an anchor on their wrists. But I can see the negative media spin on this already – cheap Apple Watch Edition uses less gold than standard 18k gold products.

    1. Jewelry is always priced differently than pure bullion. Add to jewelry pricing it’s design, uniqueness, craftsmanship and appeal in addition to the metal purity value and you most always get premium brand prices that far exceed the value of the metal. So, all the speculating experts here are legends only in their own minds , since the purity is not the only significant factor that determines retail pricing.

      1. No, but the intrinsic value of the gold is important. The cost of the gold along with other costs – alloy production, casting, machining, etc., all contribute to the cost of the product.

        We never claimed that the intrinsic gold value was the only significant factor in the price of the gold Apple Watch. Nor did we claim to be “legends,” in our minds or elsewhere. Your post was fine, up until that last sentence.

  4. This is rather silly.

    18k gold typically means 75% gold by weight (mass), not volume. 1 troy ounce of 18k gold has a fine weight of .75 troy ounces. This is the standard measurement in the jewelry industry.

    Since 18k gold by definition will be an alloy containing other metals and those other metals need not be specified, it’s inherent that the remaining 25% will be materials of differing density.

    So for example, you could mix gold with just copper adding .75 ounces of gold and .25 ounces of copper and end up with 18k gold; or you could mix .75 ounces of gold with .25 ounces of silver and get 18k gold. The copper one will be bigger by volume than the silver, and be cheaper to produce. It will also be darker and softer.

    All of this is exactly what metallurgy has always been all about, mixing the metals to create an alloy with the best qualities you’re looking for… color, hardness, and yes, volume. While (good) businesses have always been about producing the best quality at the lowest cost.

    If the 18k Apple Watch is a color that sucked, scratched easily, discolored over time or was otherwise damaged, that would be one thing, but otherwise, it’s inline with the standard of measurement in the industry.

        1. When I was in the Army running in combat boot distances of a mile or more for PT was discontinued. Too many injuries from feet to neck. Combat boot transmit shock, rather than absorb it. A couple ounces on the wrist shouldn’t be a problem. 😀

      1. The Apple Watch sports edition is the sports edition because it is lighter. They even went without the Sapphire Crystal on that model JUST to make it lighter.

  5. Also, it is not common practice and infact. rare if not stupid to use the purest form of gold (24carat) for a watch or most jewelry since it is soft and pliable. In earlier times some pendants amd medalians were made of 24 carat gold and if anyone has ever seen them they are kinked and likely bent, from handling and use, unless preserved in some encasement.

  6. Re kevicosuave comment earlier: Agree…

    As Apple stated from the beginning, “The Edition collection features six uniquely elegant expressions of Apple Watch. Each has a watch case crafted from 18-karat gold that our metallurgists have developed to be up to twice as hard as standard gold.”

    And, as describe elsewhere*, “Hardness is how we judge how easily things scratch. Some technical numbers show how a higher number scratches the same number and anything lower. Hardness is related to the Mohs hardness scale. Diamond is the hardest at 10. Talc is listed as 1 the softest. Pure gold (24 karat) is Mohs 2.5, 14 and 18 karat list at Mohs 3. Platinum list at Mohs 4.33. Sterling silver list at Mohs 2.5.”

    Not my expertise, but could one surmise that Apple’s gold/ceramic = 75/25 ratio, would yield a hardness scale for standard gold of Mohs 3 to ~6. That being the case, the amount of gold in the gold Watch would be half of what normally would be needed to achieve the current 18k standard?

    And perhaps, the Watch will be significantly less than what the pundits are forecasting?

  7. I wonder if any Las Vegas casinos are running the over/under on how long it will take before Samsung’s Gear watch starts to look just like the Apple Watch?

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