1833 Zs - Real Or Riddell?

Riddell No. 228 is probably the most worrisome of the 1833 Zs contemporary counterfeits since despite its being extremely debased, its weight will still be about right, and No. 232, which as you point out is the closest match, is also within 2% of the correct weight (I'm not sure how that sleight of hand was accomplished, particularly for the former). So your point on taking a specific gravity is well taken, although it might actually be better if it turned out to be a previously unidentified counterfeit rather than genuine....

I now have this coin in hand.

Diameter: 37.7 mm
Weight: 26.74 grams
Specific Gravity: 9.90 (suggesting approximately 63% Ag purity)

A pretty crude piece. Does have a decent ring. There're what appear to be flow marks on the periphery of the eagle side, but both dies appear to have been well worn. In any event, it does look to me to have been struck and not cast. I see about a half dozen spots (irregularly spaced) around the edge that appear to have been filed (not recently). Whether that's adjustments at the mint (which would assume it's genuine, which seems a stretch given the physical data), or a form of clipping, or removing evidence of its illicit fabrication, I'm not at all prepared to say. Like many early coins of this type, even if authentic, there're no standards that can be consistently and reliably applied. I overpaid for this, I think, but I imagine so long as it's not a modern forgery (which seems unlikely), it's worth adding to my collection regardless. Probably a good candidate for XRF.

The same small digital scale I normally use, and which I recently calibrated. Weights were taken to .01 gram, and done multiple times until I was satisfied that the accuracy of my readings was at worst within 1%. I have pretty high confidence in my results.

It's interesting that the fineness I determined is spot on with that cited by Riddell for his No. 229. However, the weight's a bit over and the die details are all wrong. Which brings me back to No.232, for which the weight is about right, the fineness not too far off, and the eagle side details a very good match (note the orientation and shape of the eagle's neck and head). But the spacing within the legend on the cap side. as you've observed, is off. So I'm not sure precisely what I've stumbled upon here.

You seem to have discovered a new Class 1 counterfeit variety made with dies that are very close to genuine. There were two mints which were known to have sold old dies as scrap metal without defacing them. The mints are Guanajuato and Zacatecas. You most likely have one of these. A coin struck outside the mint with genuine scrap mint dies on debased planchets. Many collectors have presumed these prove the stories about corrupt mint officials making substandard products. Yet US mint tests never disclosed any of these coins. The Go and Zs coins were always held in the highest regard by the US mint. I prefer to use Riddell's interpretation that the coins are either debased or countefeit, but either way they are fraudulent. His deciding factor in classifying them was the use of standard designs. So Riddell would call likely this coin Debased - I prefer counterfeit. The one thing it clearly IS NOT is a legitimate mint product.

Lucky Cuss




That is the precise purpose of the "normal" scale. It is accurate enough to determine that a coin is NOT genuine. Today's "normal" scale has essentially the same accuracy of the scales that were made available to the Chinese schroffs in 1835. That level of accuracy can identify any coin that was debased too much to circulate legally.

The reason that this accuracy level was adequate for commerce was that coins in circulation vary in weight. Weight and alloy were both essentials for circulation and for the monetary supply to be trusted.

Weight is easy - density just a bit harder.

Specific gravity determined with the same scale was also adequate to identify significantly debased coins.

A study of the silver contents of the counterfeits listed in Riddell's book will show anyone that the typical contemporary counterfeit was a coin that was far more than 10 or 15% debased. Riddell listed only 2 coins out of 290 that tested at 800 fine. The average alloy was made with an alloy UNDER 500 fine and easily detected.

Numismatic Forgeries can use the correct alloy, but even then the average numismatic forgery will not be close to correct. I typically use visual clues to ID recently made fakes.

I use a 1/100 gram Ohaus balance scale (4 beam - no springs - no electronics - direct read to 0.01g) for all coins. This is a great working scale not too expensive.

I only use a lab analytical scale in rather rare instances where I suspect a Class 2 coin made before the Chinese used density determinations for authenticity. These can fall in the 800-850 fine range which is outside mint tolerances. I also use it when I suspect Sterling silver 925 fine was used.

I use the Ohaus 310 for "normal" specific gravity testing because it reads 0.01 directly and because it has the arm to hold a water beaker. I tried the Dial-O-Matic version but hated it because of creep in the spring and an "early" death. I prefer the knife edge balance - simpler.