Hi guys! I have a question about some xrf results , regarding the metal composition? I tested 3 coins , a 1888 $1 lib, 1913 $2.50 Indian and a 1904 $20 Liberty. I know it's supposed to be 90% Au 10% Cu , but all 3 came back with 0.3% silver? I also tested another $5 1909-d indian and that has 0.2% Silver? They all weigh correctly and correct dimensions I'm wondering if this is normal and has anyone else that xrf checks their coins had similar results? I've added the pics , If anybody would know it's you guys! Much appreciated &
Something is not right here. Pre 1933 gold coins to not have silver in them. I’ve never heard of a counterfeit one having silver either.
I seem to recall that the ore that gold is obtained from also contains trace amounts of silver, and therefore gold coins do as well. Your percentages of silver are really small so it could be that. Refining it down to absolutely pure gold is probably not worth the effort just to mix it with 10% copper anyway, but somebody more knowledgeable will have to correct me on that.
It is not uncommon to find gold coins with trace amounts of silver in them. It's naturally occurring in the gold ore. And some gold ore has quite a bit of silver in it, it's known as electrum. Gold ore also often also contains copper. Which is why even with coins of the highest fineness verdigris will sometimes be seen on the gold coins.
I replied ATS. The legal specifications require 9 parts gold, the rest can be other metals. Primarily this is copper or silver (there is another specification limiting silver to 1 part in 10).
Silver is often found in gold ore. It’s not unusual to find silver traces in older, pre 1933 U.S. gold coins. After the southern mints opened in the late 1830s, it could be more than a trace. The Philadelphia Mint got on them if the silver content was too high. Too much silver made the golden color pale. The silver was removed with Nitric acid. If the early mint was running short of that, more silver could be found in the gold coins.
