1843 Mexico City 8 Reales Counterfeit?

The variance in the details of the small punches that were used to create the reverse working die could very well be a valid litmus test. I am not postulating only ONE die pair for the mintage. I was trying to point out that the Matrix block set of punches should represent only ONE punch style for a given year.

Matrix blocks were hardened steel blocks with each of the details of the 8R engraved into the block. These blocks were prepared in Spain not the colonies. The block was used to standardize the coins made in each mint. There were minor variations from mint to mint because the blocks were NOT identical at the outset.

The punches used to make working dies were made by driving softened steel rods into ONE detail on the matrix block. This created a punch that could be hardened and then used to add that one detail to a working die. That way the same Castles, the same Lion, the same pomegranate, the same crown, etc. etc. would appear on each of the working dies. Knowing what each of these small punches contained is critical to authentication of an 8R by using the details present in a photograph alone.

Now,what I really meant to convey was that because there are variations in the matrix punches used to create the working dies for the worn 1788 (thous coin) and the Heritage 1788, that I am suspicious that one of the coins is not genuine. I asked for all of the physical parameter checks we normally gather before making any statement as to authenticity.

realeswatcher You are actually postulating that in 1788 there were two sets of punches made from different matrix blocks employed at Santiago. While that may in fact be the case, it must be supported by clear evidence of authenticity for both styles. Having two matrix blocks is not at all normal at any Spanish Colonial mint. Variations of the matrix block type are often seen in the smallest branch or provisional mints because those mints often had NO matrix blocks for standardization. They made needed punches without a standard pattern.

The Fleur-de-Lis design in the central oval was made by a single punch which was created directly from a three fleur pattern engraved on the matrix block. The 8R type with the open top D assayer initial (the worn 1788 belonging to thous) uses a different sized Fleur and a different arrangement of the three fleurs. It becomes obvious when viewed side by side. In addition the 1788 posted by realswatcher also with an open top D uses the same fleur pattern.



In addition to the fleurs the outline of the shield and the central oval are different. The shield outline is heavier on the open top D and the central Oval is clearly a different shape and height. Yet I would point out that each of these features is actually an element on the matrix block and that punches used to make dies must match the matrix block.

I would also suggest looking very closely at the castles on the open D coin and the others seen in Calbetto and on Heritage. There are two styles so until we get a complete picture of the physical parameters I remain suspicious.

I asked earlier about the edge design to see if it looked reasonable. Sometimes the edge design shows when a photo is taken of the faces of the coin. The thous coin is too blurred to learn much about the edge. However, there are clues on the realeswatcher example. The circle rectangle design can often be seen as marks on the edge that follow a pattern representing the circle - rectangle spacing.



This spacing makes me wonder if the design is standard or not. When enlarged it appears that the spacings of the segments are not identical.

So I think we still need to see the edge of one of the open top D coins.

Bob, quickly... to keep things really, really simple here for a minute:

The Aureo piece I posted above (the middle photo in my post) pairs the obverse die of the NGC62 piece with the reverse of thous's piece.

Hello everyone and thank you for all the effort you're putting into this for me!
My name is Tim by the way.

I was able to take better pictures of the coin but I'm having trouble uploading them for some reason. The reverse pictures are really nice. One of the pictures shows the repunched H in HISPAN and one shows the die crack running along the top of the R and D. That seems to clearly show that the reverse die on mine is the same as the one Realeswatcher calls the "Aureo" piece.
I'm actually a little skeptical that my obverse die is the same as Swamperbob's picture from NGC. That coin has what appears to be a die crack running along the top of GRATIA, while mine has a die crack running along the bottom of GRATIA. I also think that the date just seems to be laid out a little bit differently.

Swamperbob, I really appreciate your explanation of the rim design. I have some decent pictures to show you. I can make out the rectangle-circle pattern, but there is some deformation/wear/damage around the rim so it's just not real clear (to me anyway). I stacked the coin between two Mexico City 8 Reales coins that I GUESS are real, and the rim does not look nearly as nice as it does on those two coins. I'll try to show a picture of that comparison as well.

I'm putting these observations down now so that I don't forget anything when I finally get the pictures figured out.

I hope this weekend to stop into the coin dealer in town and ask if he will weigh it for me. This is NOT the guy that I bought it from.

The best available scale for the dollar spent is, in my opinion, the all mechanical Ohaus Cent-O-Gram 311g capacity 4 beam balance with the free arm support which is good for both weight and Specific Gravity. This scale is good for S.G to the 0.1 level. To get better results than that you need a cased analytical balance accurate to 0.001g - nothing less will do.

The Ohaus is the typical College level laboratory scale. This model is a 4 beam balance and reads directly to 0.01 gram and can estimate to three decimal places. It is critical that with any scale that you confirm zero and repeatability every time you weigh anything. This scale is adjustable to make that easy.

All scales come with an inherent "accuracy level" that must be understood properly. Most digital scales are accurate to only about 2% of the total weight being measured. If you are buying raw silver a 2% accuracy might work fine. The difference works out to +/- HALF a gram for a typical dollar coin and that represents roughly +/- 25 cents at present silver prices. So if you are comfortable with a price that could be 25 cents high or low - you have an acceptable scale.

However, if you need better accuracy or wish to do Specific Gravity tests you need to do much better. The Ohaus scale is typically accurate to something better than 0.01g for a dollar sized coin. That in turn is better than a 0.02% accuracy or about a quarter of one cent for a dollar coin. Much better than 25 cents.

This accuracy level gives a Specific Gravity reading with a precision (scientific notation) of 0.1. So a result of 10.3 for SG means "somewhere between 10.25 and 10.35". This in turn translates to a fineness between 870 and 920. This accuracy is good for detecting about 99% of counterfeits and forgeries you will encounter.

I also suggest using different scales for different tasks. DO NOT USE ONE SCALE FOR ALL PURPOSES. Typically a scale works most accurately near the center of the weight range it was made for. So large capacity scales used to weigh bulk coins will actually be less accurate when attempting to weigh a single coin or a batch of coins near the upper limit of the scale's capacity.

A good rule of thumb is to NEVER use a scale intended for Specific Gravity to weigh anything more than a single coin.

So what does this scale cost?

There is a new version of a Walter scale which I have never used but seems to match the Ohaus. https://www.amazon.com/dp/B00LOVPVWG?psc=1

A band new Ohaus scale of this type costs $ 215. See Amazon Prime: https://www.amazon.com/Ohaus-Cent-O...JZNCR2MNM342

On ebay there are many examples. Nearly new:

http://www.ebay.com/itm/Ohaus-Cent-...282179417708

Used but serviceable examples are much cheaper. For example:

http://www.ebay.com/itm/Ohaus-Cent-...162416087108

The difference between a new and used scale would be the ability to accurately estimate the third place decimal (and repeat the test 3-5 times without any drift). Even used this scale is fine for what you need to do to get a 0.1 level specific gravity determination for a dollar sized coin. For that reason it is accurate enough to detect 99% of counterfeit types.

They key element found on the Ohaus scale is the free arm support pan which you need for SG. Personally, I do not like the Dial-a-Gram type of the same model scale because the spring can stretch rendering the scale un-usable after only a few hundred uses. Make sure you get the stainless steel pan that comes with the scale to avoid having to make an added weight to compensate for the loss of this pan. I also suggest that you avoid older scales because of the knife edge - the balance pivot which can corrode or wear with long term use. So I would also pass on any scale with visible corrosion.

This type scale is better and will last longer while retaining accuracy better than any of the inexpensive digital scales.

Digital electronic scales are fine for determining weight.

So Lucky Cuss I agree with you that one of the cheaper digital scales is fine for the task at hand. I have several scales like this and usually travel with one. I use them to weigh every coin when I first see it. However, I also expect to replace these scales every few months because they eventually drift.

The problem with digital scales is that after a period of time - the weights displayed start to drift. The same weight for one coin can not be repeated time after time. I have tried using better grade electronic scales that sell for up to $ 50. These are good for an average of about 2-3 years. They work fine for weight determinations but will suddenly fail with no warning. They can not be repaired.

Last week, I was weighing a lot of dollar sized coins that came in the mail and as I always do, I confirmed the weights by doing the group of 10 coins twice. After the second run through, I noticed that the weights for the same coins varied. I changed batteries and the results of the 10 coin double run were different once again. Then I tried weighing same coin 10 times in rapid succession and the weight varied by as much as 0.2g in both directions. This is typical of the sudden failure of electronic scales. This particular scale lasted over three years, so it was a success from a cost perspective.

The simple reason for coin shops not using Ohaus scales is that no coin shop I know of actually checks Specific Gravity of anything. As I said above, electronic scales are fine for gross weight of coins and metals just not for accurate SG tests.

Scientific authenticators on the other hand do perform SG tests use far more precise scales. Typical of these are Ohaus types or cased analytical balances.

I believe every coin collector should know how to perform SG tests as a form of self protection.

Hello everyone. Thanks again for the valuable input!
I never really had a need for a scale before. My coin collecting went on hiatus around the year 2000, but I had been collecting mainly Indian and Lincoln Cents, with certain small peripheral interests (like these Spanish coins). I've been reading quite a few posts about early Mexican and Spanish coins, and I think that if I do go after them in earnest now I will need to get some good books and a good scale!

I took my Santiago coin to a coin dealer on Saturday. He said he could not determine the metallic makeup of the coin without shaving off a small piece, so we didn't do that. He weighed it though and got 26.62 grams.
It is non-magnetic.

I hope these pictures came out better than the last. The edge pictures were taken at 12-3-6-9 o'clock.

Hi Swamperbob. Thank you!
I have to say that spot at the top of the D never stood out like that until I enlarged that picture. I'll have to try to focus on it close up and see what's going on there. It does seem to conform to the shape of the D, and the missing part of the D on my coin seems to be larger than the missing part of the D on the coin with the same reverse die that Realeswatcher showed us. Is it possible that a section of the D filled in with bits of metal that were squeezed into the die crack? It also seems that the top of the R on Realeswatcher's coin is missing, but on mine it is complete. Of course, that would be exactly the opposite of what's happening to the D!

The edge design as you can see is a little bit messy. Scrolling down, my second and fourth edge pictures are opposite sides. There does appear to be a gnarled-up area of rectangles and circles on those two sides, but that's the best that I can see.