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 Replies: 21 / Views: 2,649 |
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New Member
Australia
45 Posts |
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 &      |
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New Member
 Australia
45 Posts |
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Pillar of the Community
United States
2003 Posts |
Sorry I can't help you mate, I don't have any experience with the XRF but those are some beautiful gold coins. Congrats!
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Moderator
 United States
54280 Posts |
It is normal.
Show your financial support of the Coin Community Family (click here)See my topic on Mexican Numismatic Medals (click here) |
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Pillar of the Community
 United States
1502 Posts |
Trace elements - absolutely normal.
I swing a metal detector and have a knack for finding dirty old coins. Dirt coin restoration projects - https://www.prodetecting.com/restorationsDirt coin restoration blog - https://www.prodetecting.com/blog/ccawDirt coin dig videos - https://www.youtube.com/@prodetecting |
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Pillar of the Community
United States
4589 Posts |
You are wrong about the composition. https://maint.loc.gov/law/help/stat...2s3ch131.pdfQuote:
SEC. 13. That the standard for both gold and silver coins of the United States shall be such that of one thousand parts by weight nine hundred shall be of pure metal and one hundred of alloy; and the alloy of the silver coins shall be of copper, and the alloy of the gold coins shall be of copper, or of copper and silver; but the silver shall in no case exceed one-tenth of the whole alloy. This allows 0%-10% silver, which implies 10%-0% copper as the other 90% must be gold. -----Burton 50+ year / Life / Emeritus ANA member (joined 12/1/1973) Life member: Numismatics International, CONECA Member: TNA, FtWCC, NETCC, EveryCountry (online) coin club Owned by three cats and a wife of 40+ years (joined 1983) Author: 3rd Edition of the Sample Slabs book, https://www.sampleslabs.info/ |
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Pillar of the Community
United States
2281 Posts |
.3 is so negligible, nothing to worry about.
You realize when you know how to think, it empowers you far beyond those who know only what to think.
-Neil deGrasse Tyson
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Pillar of the Community
United States
3343 Posts |
UK sovereigns and French 20Fs also use copper as the secondary metal with the gold. English guineas used an equal mixture of silver and copper for the alloy, according to this 1776 report: The English Standard for gold is 22. carats of fine gold + 2. carats alloy. I.e. 1/12 alloy of silver and copper in equal parts.https://founders.archives.gov/docum...1-01-02-0214"Two minutes ago I would have sold my chances for a tired dime." Fred Astaire
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Pillar of the Community
United States
4589 Posts |
-----Burton 50+ year / Life / Emeritus ANA member (joined 12/1/1973) Life member: Numismatics International, CONECA Member: TNA, FtWCC, NETCC, EveryCountry (online) coin club Owned by three cats and a wife of 40+ years (joined 1983) Author: 3rd Edition of the Sample Slabs book, https://www.sampleslabs.info/ |
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Pillar of the Community
United States
6381 Posts |
I think I read somewhere that native California gold typically contained over 90% gold, mixed with silver and copper. Each batch of gold used for coinage would be adjusted down to 90% fineness by adding copper. The resulting coins would all have correct gold content plus variable levels of silver and copper.
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Bedrock of the Community
United States
10982 Posts |
Completely normal. BStrauss3 makes a strong point above.
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New Member
Australia
45 Posts |
have any other members had similar results? I think the better xrf machines can detect the more minute percentages too
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Pillar of the Community
Portugal
655 Posts |
89.4 Au in a double eagle is a deviation I would not expect. Modern mints use to be very precise in gold content. But the coin certainly seems genuine. I can believe it is within the error of the machine.
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New Member
Australia
45 Posts |
i found a shop that has a "cheaper generic brand " XRF machine and this is the results for the double eagle,,,,its not detecting any silver at all unlike the Thermo Fisher Scientific xrf machine that shows 0.3% Ag. mmm interesting maybe the Thermo Fisher Scientific XRF is more powerful and can detect the smaller trace elements or the generic chinese XRF is just calibrated better or somthing? for my curioisity I'm going to get all my coins tested with the generic XRF and see how they go :)  |
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Pillar of the Community
United States
4589 Posts |
-----Burton 50+ year / Life / Emeritus ANA member (joined 12/1/1973) Life member: Numismatics International, CONECA Member: TNA, FtWCC, NETCC, EveryCountry (online) coin club Owned by three cats and a wife of 40+ years (joined 1983) Author: 3rd Edition of the Sample Slabs book, https://www.sampleslabs.info/ |
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New Member
Australia
45 Posts |
that was a very interesting read! cheers for that Bstrauss
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Replies: 21 / Views: 2,649 |
Posted 02/22/2025 05:20 am
