Impurities in native California gold.
RogerB
Posts: 8,852 ✭✭✭✭✭
One easy means of testing anything said to be made from native California (or Oregon) gold is to run an X-REF test for impurities. Here's a short statement dating from 1889 that might help.
"All California crude gold, gold bars, etc., received at the mints, that portion which is not gold and the alloy, silver, constitutes the so called base metals, of which there are generally from ten to twenty parts in one thousand, of antimony and lead, copper, iron, often bismuth, traces of platinum and palladium, and frequently a small percentage of iridium.
"All gold bars received in San Francisco from the Pacific Coast are stamped with the gold fineness and value thereof by the assayers casting the same, the silver contained therein allowed for at the market rate. California gold bullion generally contains, on an average, 12 per cent of silver in weight, while that of Australia has averaged but 5 per cent, though in the past few years, silver in the Australian gold has materially increased."
[From: Annual Report of the California State Mining Bureau – December 31, 1889.]
Trace amounts of Iridium and osmium are also present in nearly all coins made from refined California gold until about 1870. Technology was not sufficiently mature to allow economical extraction.
Comments
That is so cool to know. So, gold bars supposedly from California gold rush can be verified. Not worried about old coins but could weed out counterfeits, right?
bob
Roger, do you have any more info on the X-REF test?
I am assuming this is X Ray Fluorescence (XRF) which is in common use today - but not really made practical until the 1940s, well after the coinage in question.
“In matters of style, swim with the current; in matters of principle, stand like a rock." - Thomas Jefferson
My digital cameo album 1950-64 Cameos - take a look!
The measurements he refers to were not made with XRF but 19th century assays.
I would assume the TPGs have done a more careful measurement using modern techniques which would provide better numbers, particularly of lower levels of trace metals. A statistical analysis would also provide a better sense of the tolerances on those amounts.
I was suggesting the modern test methods would be used both to help validate authentic west coast gold, and to establish a baseline for treasure recovery gold.
I do not, however, presume that TPGs have performed careful tests using X-REF or other nondestructive means. These are all for-money businesses and blind research is not on their common list of activities. That is not meant to be cynical -- just realistic.
Thanks for the clarification - I suspected that was the case.
Old assays were done the old fashioned way - wet chemistry and fire assays - probably others. Nasty, time consuming, and not particularly accurate by today's standards.
I am reminded of the days when I made auto catalyst. In the early days we received platinum, palladium, and rhodium where trace elements were purposely added to provide a trackable fingerprint in case the metals were stolen. Most crooks did not know this was even done.
In later years as security improved, the trace elements were removed and that system disappeared into history. Typical purities of 99.999% left little room for trace elements.
“In matters of style, swim with the current; in matters of principle, stand like a rock." - Thomas Jefferson
My digital cameo album 1950-64 Cameos - take a look!
A little isotope adjustment can do wonders.
Elemental fingerprints (in this case, metallurgical) are even used in forensic crime solving.... Although it was not possible sixty or seventy years ago, it is common today.... Cheers, RickO
Around 12 years ago, we had a large number of Ford bars/"proofing ingots" etc. tested and they didn't conform to the trace elements you'd expect to find in California Gold. You would think that a competent forger would use native California gold to make a fake CA gold bar, but evidently the people who made those pieces couldn't be bothered.
What is now proved was once only imagined. - William Blake
EXACTLY!!
I've always been astounded that the Ford fakes (including things like the Miner's Bank Crimped Border pieces and the prooflike Assay $20s) fooled anyone. The fake coins and bars from that cabal always look like toys to me.
What is now proved was once only imagined. - William Blake
In the time period the fakes were made, great trust was placed in several prominent "numismatic" names and companies.
A very small group of outsiders advocated for empirical validation, but it took 30 years for them to be accepted as correct. In that time, how many fakes were made, sold, resold and donated to ignorant or complicit parties, we'll never know.
Given the number of pieces that I've seen in the last 15 years, there were a lot more Frod fakes than you'd think. Apart from the bars, you have all the fake USAOG $20s, the weird fake Humbert and USAOG whatsits (there were at least two dozen varieties of these or more), a fake Pacific $5 struck over a Classic Head $5 that hasn't gotten any real attention, a Conway $5 over an 1845 $5. the various fake $20 Clark Grubers (both prooflikes and overstrikes), the aforementioned Crimped Border Miners Bank that were recently condemned and bought back - one of which is offered here:
https://bids.holabirdamericana.com/lots/view/1-QKTFF/miners-bank-10-gold-piece?utm_source=lofty&utm_medium=web_primary_button&utm_campaign=product_page
the Saudi gold disks, etc., etc...
I regret not being in the business when Frod was active, as it would have been a lot of fun to expose these while he was alive.
What is now proved was once only imagined. - William Blake
Regulated -- Thanks for the link. I was not aware that Oscar Meyer wrote auction descriptions....
It's one of the only places that you can see a good photo of one of the fakes.
What is now proved was once only imagined. - William Blake
When I was researching my 1848 CAL $2.50
I found this information also.
http://news.coinupdate.com/qa-is-the-1848-cal-quarter-eagle-a-private-or-territorial-gold-issue/
"These coins from the gold discovery that ushered California into the Union ......have a distinctive brassy color imparted by the high silver content of California gold, .......with several specimens being possessed of prooflike surfaces."
I actually went to visit the late Henry H. Clifford before he passed away and we chatted the afternoon
away talking about the S.S. Central America and other stuff. I showed him the Life magazine article which featured
images of the treasure that was recovered. Henry ended up with a lot of questionable material, which he had obtained
from John J. Ford Jr. He sat in a wheel chair and held a drink in one hand the entire time
his mind was still sharp...nice gentleman....he passed away in 1994....RIP Henry
When Stack's was digesting the Ford Collection for its auctions, it quietly shipped 701+ ounces of questionable gold and/or silver items to a refinery in the Midwest to quietly go away. As fate would have it, a dealer friend of mine happened to be at the refinery that day, and the refinery must have said "Hey look at this!"
Would love to have seen individual assays on those pieces.
Clifford had a lot of Ford goodies, but he had great stuff too. Can anyone confirm the story about the mystery bidder who bought up a bunch of stuff out of his sale, then disappeared with it (ostensibly without paying)? I've heard it from a couple sources, but the details seemed inconsistent.
I believe Clifford was the first person to buy a Crimped Border $10 from Ford.
What is now proved was once only imagined. - William Blake
Interesting !!!
I know I've seen a decent amount of fractional california gold with nice toning. More so than most other US minted gold coins. Wonder if this has anything to do with it?
That's the silver in the coin toning. The services don't really understand it and often undergrade toned cal gold like this.
What is now proved was once only imagined. - William Blake
This letter to a US Senator might help a little with the gold content of these items. It would also explain the excessive tarnish and corrosion often seen.
Is this why some California gold tones/ages differently than others? Why it actually looks like "old gold"?
Depends on what is meant by "California gold."
if you mean partially refined territorial and USAOG pieces, possibly. Normal mint gold will contain only gold copper and a little silver + traces of platinum/palladium. Iridium, if present, will be tiny flecks.