Mexican Pillar Dollar 1741

The pictures are not all visible to me - but the edge views I can see on the post do NOT belong on a 1741 Pillar dollar. In fact they do not belong on any Pillar Dollar. They are associated with a type of Numismatic Forgery.

The weight is correct but the SG would likely prove to be about 9.0 or less (a copper nickel variety).

I don't see all the pictures, but from those I see, I totally agree with Bob :)

The rest of the photos only confirm my original opinion of the coin. It is a Numismatic Forgery that is successful because of the number of 1741 shipwreck coins recovered from the Rygersdal in 1747.

The Rygersdal wreck was one of the ships that carried a significant number of 1741 coins as I recall.

Forgers will throw names around at times to try to pass casts as corroded originals.

According to the numismatist who sold me the coin his brother, deceased a couple years ago, changed this pillar dollar with someone, supposedly a diver, in the USA, Florida was mentioned, for a couple of cobs. I checked the internet and discoverd that the Reijgersdaal sunk in 1747 off the coast of South Africa (http://www.sunkentreasurebooks.com/...wrecks.htm). If I am to believe the numismatist that sold me this coin, this coin should be of a shipwreck off the coast of Florida. The diver supposedly knew of a find and dove every once in a while a couple of coins. We will most likely never know if this story is true or not. But at least it is an interesting story.

Here are the pictures you requested MathieuMa although I have already made up my mind and decided to keep this one. Two independent expert numismatits have already looked at this coin and both consider the piece authentic. One of both numismatists being the firm and auction house Schulman in Amsterdam. Their numismatist said that he would without any doubt auction this piece as an authentic pillar dollar, not that I would be interested selling it. That is not the reason I collect coins.








If this is a forgery, it would be the best forgery I have ever seen and certainly worth while keeping it. By the way I am trying to see if I can get this pillar dollar analyzed via XRF however finding a company that is willing to do this does not appear to be that easy.

Regards,
JO3023

You start out saying:




There is no support in any "good" reference I am aware of to edging with one die. The one die process was used by forgers as was the roller die applied edge.

All 8Rs I have examined that were absolutely genuine were edges with a two die edger similar to a Castang machine (US reference).

You also say



The number of denticles was not a standard number - it varied as did the die face diameter. The target size for the coins was identical but some mints are noted for slightly different diameters which alters the circumference. The dies were not hubbed so variation is possible. Personally since a circle consists of 360 degrees, I think the target number of dentils would be 180 (2 degrees each). So 178 to 182 is a good approximation for a manually punched perimeter.

In my book I tried to introduce to coin collectors the subject of gold content as an absolute determinant of authenticity in old Mexican coins. The theory is simple - until the 1870s it was impossible to part gold and silver to a level of 999 fine. In the late 1700s the level was much closer to 990 fine. Gold contaminates silver because the Patio process and cuppelation were not adequate to refine and separate gold and silver.

The refining process in all of the 1700s relied on Mercury amalgamation it was called the Patio Process. Gold and silver both amalgamate with mercury so the result was a mix of the metals (Au and Ag) based on the composition of the ore. Because Platimum does not amalgamate with mercury I discount that metal as a marker. The patio process left Platimum behind. XRF tests when not properly interpreted produce false spikes for Platimum because it's XRF signature is close to gold and can be incorrectly interpreted. Colonel John followed that line of thinking and may have published an article or two before I advised him that the patio process did not extract platimum from the ore. He has since abandoned the theory that a ratio of Au and Pt existed.

The amount of gold found in the silver veins needs to be examined because it varies based on the geology of the mines. The best source for data are recent borings and XRF tests done on the core samples from all of the active and abandoned mines of Mexico. There are several on line sources.

When the Valencia mine was in full operation 60% of all silver coined at Mexico City came from that one mine and the gold contamination of silver from that mine was high (as are all known Guanajuato and Zacatecas deposits). Valencia silver is most easily seen in XRF tests of coins dating from 1780 - 1830 but similar lower gold contents are seen in EVERY year struck in Mexico. The discussion of this topic is rather new in numismatics but was published 30 years ago in forensic authentication publications. I first used XRF testing for authentication in the 1990s when I had access to a testing lab with a then state of the art machine. Tests were to 1000 ppm range but gold was always present in the coins from the Go and Zs mines.

About 2005 I expanded XRF testing to include other issues.

After testing over 200 coins I can say that I have yet to encounter a genuine Mexican coin with less than 200-400 ppm of gold.

Based on your comments and your obvious interest in the historic 8 reales series I would recommend The Milled Columnarios of Central and South America: Spanish American Pillar Coinage, 1732 to 1772 by Frank Gilroy. This book provides excellent historical background, detailed discussion with exhibits of each coin's characteristics, and a glimpse into how the coins were made. Reading this book has certainly enhanced my own understanding and appreciation of these coins.

Hope this helps.