I'm a bit puzzled that this is news.<p>The technique of using metal or stone powder with resins to create fake metal or stones is used since years.<p>When I was living in HK, in Sham Shui Po, I always wondered why there were these street stalls selling huge blocks of jade for cheap. Later a local friend told me it was just blocks of resin with embedded jade powder and other stuff. E.g. other stones ground up to simulate imperfections and dyes for the resin.<p>When used with metal powders to create sculptures, jewelry, etc. the technique is called 'cold casting'.<p>See e.g. <a href="https://www.youtube.com/watch?v=7VBVU3FNt-s" rel="nofollow">https://www.youtube.com/watch?v=7VBVU3FNt-s</a><p>Ofc., people do this with gold too: <a href="https://www.reddit.com/r/ResinCasting/comments/bfiixq/cold_cast_gold_dice_set_with_bonus_skull/" rel="nofollow">https://www.reddit.com/r/ResinCasting/comments/bfiixq/cold_c...</a><p>The problem with all this is that these materials have plastic-like properties. The article mentions the sound the fake gold nugget make when hitting a surface sounding like plastic. This is one of the issues.<p>The weight is another one. Surface feel/texture depends on various factors.<p>The bottom line is: these materials look like the real thing but they don't feel/sound/behave like it.
> No one wants to wear a heavy watch on their wrist, even if it’s made of real gold. After a time, it becomes uncomfortable and annoying.<p>This is a huge assumption. Wine tastes better served in a heavier bottle. More weight objectively does something with value perception.
A much simpler approach is to alloy gold with titanium. The resulting alloy is stronger and less dense than pure gold. Carat weight is determined on a weight fraction and because titanium is low density, a relatively large volume of titanium can be alloyed with a small volume of gold and still have a high carat number.<p>One particular gold-titanium alloy is significantly harder than most steel.<p><a href="https://phys.org/news/2016-07-lab-titanium-gold-alloy-harder-steels.html" rel="nofollow">https://phys.org/news/2016-07-lab-titanium-gold-alloy-harder...</a>
Apple did something similar with their ceramic/gold composite watch - there's some good info here:<p><a href="https://leancrew.com/all-this/2015/03/apple-gold/" rel="nofollow">https://leancrew.com/all-this/2015/03/apple-gold/</a><p>Unsurprisingly, paying a huge premium for a watch with less gold in it wasn't very appealing to people. Interesting idea though.
> <i>Lovers of [...] heavy jewellery will be thrilled.</i><p>Presumably not? Lovers of gold jewelry, who <i>don't</i> like the weight may be, however.
> <i>The conventional mixture is usually three- quarters gold and one- quarter copper, with a density of about 15 g/cm3.<p>That’s not true for this new lightweight gold: its density is just 1.7 g/cm3. And nonetheless it is still 18- carat gold.</i><p>Imagine comparing jewelry that is all “18 carat”, but some of it has 10x less actual gold. Seems like there will be a lot of fraud happening during a period when customers are not yet aware that the minimum amount of gold in an 18 carat piece has been reduced 10x. People will just hear “18 carat” and assume it means the same thing it meant before.