Tim Cook and Jony Ive have both spoken numerous times about the Apple Watch Edition being more scratch-resistant than standard 18-karat gold, describing it as ‘twice as hard’ as standard gold but but without explaining how. A patent application (via Leancrew) appears to explain this–and shows that Apple saves money on the gold into the bargain.

18-karat gold isn’t pure gold, it is defined as being 75% gold by weight. The remaining 25% of the mix is usually made up of one or more other metals, with silver and copper popular choices. The Apple patent describes mixing gold with low-density ceramic particles instead of metal.

Because weight, not volume, is what defines the karat gold standards, Apple’s watch could use less than a third the gold of a conventional alloy while still qualifying as 18-karat gold …  expand full story