![]() But then, most think electrum can only be native gold. We agree with Eion MacDonald (Nature and History of Gold, 2007) that any Au-Ag alloy (trace copper-Eion says less Cu than Ag) can be considered electrum. The more we have studied electrum, the more it seems electrum is very confusing because most think it's more than a name for an alloy and that the distinction between native gold and electrum seems arbitrary anyway. The verbose point is that electrum can be found that looks like silver instead of gold. My understanding is that prospectors still sometimes find silver-colored gold nuggets in that region. Ancient sources often claimed it was 50/50 (and so some people consider electrum 50/50 thereabouts the definition of electrum.) Archaeologists have had no success finding any such native alloy there (Turkey) and some books say this alloy is impossible but 55-60% Au Electrum is known from Comstock. ![]() ![]() The ancient Lydians were said to pan electrum from the river that ran through town. This would explain why people think electrum is rare. Placer and plenty of rich deposits maybe less Ag but much more than 15% Ag becomes rare natively due to the workings of the Au-Ag system in deposition. My understanding is native yellow gold can average 12-15% Ag. Some say "Electrum is an alloy of gold and silver that varies in its natural state between 65% and 85% gold." This makes sense because these points can be approximately seen by color as above. Lots of written sources define 15% Ag or more (with little Cu) is Electrum. Now this 20% Ag electrum thing is not a technical definition, it's just like an internet-spawned custom. Likely because the ancient Lydian Greeks made the first coins with around 50/50 electrum that would have looked silvery white. The ancient Greeks called electrum white gold. Greenish electrum ranges from pale yellow-green to silverish with a green tint. They add other things, Cu, Zn, and maybe 2-4% Cd (Cadmium) for deeper greens and other properties, although 75% Au-25%Ag is an alloy sometimes listed as "soft green gold." Soft because the silver doesn't harden the alloy like Cu would. And, the green color of electrum is very subtle compared to green gold alloys typical of today's jewelry trade. At that point it would become silvery white-look similar to silver. It would be a green gold from there to about 45% silver or so. ![]() Click to expand.For electrum (Au-Ag) alloy, you likely wouldn't see gold color from 20 percent silver or more, which is why the trade tends to define electrum that way. ![]()
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