1789 8 Reales

Well with no gold or platinum at 100 ppm - there is one thing we know as an absolute fact




The fact that NGC or any/every other living expert says it is real does not change the facts. The coin was not made before 1870.

Next question - knowing the facts do you view the coin as genuine or not?

I honestly do not know if this coin is real or fake (leaning towards fake). Maybe the XRF analysis is wrong, maybe the interpretation is wrong. There was a false positive for selenium that maybe masked the gold and platinum. Maybe there was a silver vein that did not have gold or platinum.

The more I learn about these coins and how they were made, the more I realize how little I know.

Here is a flawed analogy: I paint a light with translucent paint. Everyone says its blue, painters, artists, my wife, everyone says blue. Then we read it with a spectrometer and the spectrometer says red. What color is the light?

There is as much cost into the investigation as there was in the purchase of the coin. This is fun. What about crack it, reshoot the XRF with a different lab, and send it to PCGS?

^^^^ I would think that to be true - Bob or John, anyone in the mining field (!), thoughts?

BTW, for reference, here is the exact location of Westwood's pics:
https://goccf.com/t/142623&whichpage=7#1493817

Westwood, PCGS/NGC are going to see your piece as perfectly genuine 1000 times out of 1000... It's struck, the silver is good, the surfaces are good and are a product of older vintage, the design is proper beyond any usual doubt to any normal advanced coin handler's eye, undoubtedly the piece feels "proper" in hand, it's not a Sheffield/Birmingham plated piece, not a modern fake... even some planchet stress and uneven strike for good measure.

All of that is exactly Bob's point - bullion restrikes were/are essentially perfect recreations (at least to the naked, untrained eye, even in modern times... and certainly for their intended purpose). Now, Bob/John/Gord are going to lay out certain traits to examine/verify pieces... many of which Bob has alluded to/stated here over the years... but as I see things, I don't think any of that could be as simple and decisive a litmus test as the XRF. So, as was said, IF XRF was done correctly here, a piece like this is a smoking gun with no other explanation.

Rescanning this thread, CoinWorld brought this up - did you get another piece tested on that machine... maybe something like a 4R where the restrike question doesn't apply?

PS - Bob and John, have you guys zapped any Micro-O pieces for comparison?

The silver restrikes (more correctly counterfeits) are in a stand alone category that was at one point in History well known by collectors but which has since been forgotten by the collecting community as a whole.

I believe this happened (more or less intentionally) in the 1800's because there was NO WAY at that time to tell one type from the other with absolute certainty. The result of not knowing how to accurately tell them apart was that both dealers and collectors treated them all as identical and "genuine" unless they were made with a fraudulent assay or used a badly rendered design. That in turn made the varieties that were copied more "common" and the prices remained low.

The inability to distinguish the types was true for more than 170 years, but it is no longer true because of scientific tests.

In 1835, the Chinese were introduced to western science and for the first time used specific gravity to confirm an alloy to within 10 points of fineness. But collectors seem to have forgotten this test too. More recently SEM and then XRF became common non-destructive tests to establish accurate assays of metal objects.

Science is a tool that I want to see used more universally in authentication. Determining authenticity is not a mysterious undertaking and should not be hidden behind a smoke screen of opinion based on undefined "expertise".

If people want to ignore this inconvenient fact (that silver counterfeits do exist) fine, but as science marches on, I expect that the methods of testing will improve and that more and more of the restrikes (counterfeits) will be exposed for what they really are.

We always need to keep in mind that scientific theories are never actually "proven". However, when they predict reality correctly over and over again, they are "confirmed repeatedly" to the point where a given theory moves to a virtual certainty.

realeswatcher You ask if this statement is true?




The answer is that in theory, yes it is virtually impossible to find silver this pure in New World deposits particularly those of Mexico. Gold, silver and to a lesser extent platinum are all heavy elements that rise with volcanic rock (magma) especially along the continental subduction zone where the Pacific tectonic plate meets the North American plate. Mexico like Nevada has rich veins of silver and gold which rise TOGETHER because of a particular combination of factors which resulted in magma intrusions millions of years ago. These were followed by a second later round of hydrothermal vents giving rise to a mixed assemblage of silver AND gold. The silver ores (because silver is reactive) are always found mixed in forms (like sulfides) that never achieve the state of purity being postulated by the test results expressed for the Westwood Arms coin.

Mexican silver ores typically yield more gold than US mines but the ratio of metal extracted from the "rich" ores is normally expressed in grams of silver per TON of material mined. That is NOT pounds of silver per ton but grams. A high yield area like Guanajuato reached 3000 grams per ton. That is great about 8 pounds of silver for every ton of rock processed. Silver is normally found at 0.07 ppm in volcanic rock but the secondary hydrothermal leaching concentrated that to much higher levels (several hundreds or thousands of times more concentrated) that produced the commercially valuable deposits of Mexico.

Think of it this way. The coin in question tested NO gold or platinum at a level of 100 parts per million (ppm). That means there is LESS than one part per 10,000. That is LESS than one ounce of gold mixed into 833 pounds 4 ounces of silver. The amount is truly miniscule which is why it was not essential to remove gold which traded at the time for approximately 16:1.

The tests run on genuine 8Rs which show no signs of being restrikes (including Cap and Ray varieties as controls) contain roughly 0.3 to 0.4% gold and normally slightly less platinum. That is 3 to 4 parts per thousand. Ideally I prefer to see a test run at 10 or 20 ppm just to be safe but 100 ppm is actually adequate. But less than 1 ppm is 30 to 40 times lower than the MINIMUM result using a laboratory grade XRF. The highest I have seen reported (not confirmed personally) is an astonishing 2.8% gold. I have one Zs Cap and Ray in my collection from Zacatecas that tested just over 2%. Zacatecas and Guanajuato are the most heavily contaminated mines tested so far.

I hope that answers the question as to the likelihood of finding pure silver in the Mexico.

realeswatcher Also asked:




Not yet, but I have bought several examples of the micro O types that I hope to get tested before long. I do expect them to test no gold at 100 ppm since they were made after 1902 according to Leroy Van Allen. The best theory places the actual date of production as somewhere between 1902 and 1940.

Susuman I want to thank you for your very succinct supportive summary of the scientific method as it was put to the test in the Westwood Arms case.

Westwood Arms You say:




That issue is precisely why I believe visual clues which correlate with proven counterfeits are such a promising area for study. Once a group of coins having a specific feature or trait (one die or die punch group) is proven to be a counterfeit by XRF (several tests yielding the same results) then that entire GROUP of coins can be treated as counterfeit and NOT EVERY single coin of the group needs to be tested.

Over time such groups hold the promise of isolating counterfeits now entombed in plastic coffins as if they were real.

Encapsulated counterfeits are a serious problem growing larger EVERY day.

Over the past few months I know of several dozen coins encapsulated by NGC as genuine that came from a single Mexican hoard. I own 8 examples from that same hoard. NONE of these 8 tested as 903 fine silver using Specific Gravity. NGC does not yet use SG to test all submissions. That, in my opinion, is a BIG and growing problem.

I do not know about you - but I would be seriously concerned how a coin with only 70% silver by SG test could be graded "genuine". When made that coin was a fraud. If it was made with genuine mint dies that is one thing but if as I believe the dies are themselves spurious - where does the fault lie?

That is enough on this topic - I just hope collectors in the US get the hint that Grading is NOT the foolproof system it was once believed to be.

Yes you know the hoard. So far I have only SG tests on Zs varieties but I have been collecting pictures of all the coins as they are posted. I suspect but am not prepared to discuss a working theory on origins.

Here are some odd factors to consider:

The number of new die varieties appearing is odd.

The number of essentially MS coins from a period 1811 to 1820 is odd.

The grouping of mints seems odd.

The number of severely eroded dies is odd for a "new" find.

Since no definitive tests have been run, I am still working on a gut level. So I would prefer not to open the subject unprepared. Too many open issues that would muddy the waters right now.

The survival of the alignment arc is not necessarily proof of forgery - just proof the die was not finished in a normal manner.

I would leave the subject alone until the whole extent of the hoard is known and more tests are run.

Susuman You must have a Civil Engineering background as I do. I had not yet approached the data that way but I now believe I see your point. Since the silver in the coins varies widely in percentage and there are several possible contaminants, the three components Ag, Au and Pt expressed as a percentage of the coin's weight is useless since they do not add up to 1.00. However, if we treat the sum of the three components as if that was 1.00 for each coin (a forced balance of the three components), we should theoretically come up with a rather predictably clustered plot. I will try that if I can get the raw data on platinum from John.

I also might try different plots to see if they are of value or not. I have 50 or so detailed results here all Mexican. The other results I have are listed with each coin in the bank. I know John must have a far larger data base than I do - he has tested many specimens.

John in fact disserves the credit for the theory that Platinum as well as Gold was a standard contaminant in Mexican silver. I knew about and had been testing for gold as a contaminant for over 15 years but I was unaware of a more or less standard platinum contamination until very recently. So I have mostly 2 point data for the coins tested before I knew John.

I think an interesting plot would be for coins from each mint (or mine area) using date, Au/Ag ratio and Pt/Ag ratio. Then I could merge the various plots.

I am not at that point yet however.

Mexico City drew supply from several mines. Guanajuato and Zacatecas mines were largest and eventually mints were built in both locations to avoid shipping bullion to Mexico City. Placing a mint near a productive mine seems to be normal practice.