Mexico Un Peso 1901 - A Clear Case Of Casting Specimen?

I would call it cast- the die breaks come from the original coin- the clues to me are the odd dots where they don't belong- after 1st A of Mexicana, many of the dots around the rim have smaller dots around them- places where it is harder to clean up the dies/moulds, above 2 of 902 fineness, above S of Peso. Around the dots below Peso shows the worst lack of proper details in the dots.

Click on "Obverse" and "Reverse" in the first post above, swamperbob:

Hi-Res of Obverse
Hi-Res of Reverse

Yep! Counterfeit, but nice touch with the die cracks.

I just got back to looking at this thread and wonder if the coin has been weighed and if you can determine the SG?

The Strong Peso series was struck on a collared steam powered press. This is a technology that is far different from the open sided screw press used during the striking of the 8 Reales series. The coins produced by the two technologies will inherently look slightly different especially in the area of the collar.

Because originals will look different, so will some of the clues used to diagnose a forgery.

So back to the coin. Why specifically are we calling this coin a CAST? Because quite frankly from the fantastic pictures you have taken I would say this one was REAL.

The first comment was

I presume you are referring to the die cracks that travel around the coin through the letters. In a press with a collar - the collar changes the way pressure is distributed over the die face during the impact. The collar forms a rigid retaining surface so that the pressure near the edge INCREASES. In an open screw press the pressure at the edge of the die DECREASES. This change in pressure distribution causes the dies to fail in ways they did not fail before.

As you become more familiar with striking methods you will notice that how a die fails actually changes with the machinery. This is one such case. At the edge of a Strong Peso you often find this connected ring fracture around the die perimeter. It is one of the problems that plagued the mints during the transition to the collared presses.

The appearance of the cracks in the photographs looks good to me. They are slightly worn at the tops matching the wear level seen on the coin itself BUT they are SHARPLY DEFINED where they meet the field. In general all of the details show this same SHARP transition which is prima facia proof that the coin is not cast. To replicate this sharpness in a cast coin is an advanced technology only recently observed on coins cast from fine matrix plastic impressions.

The second comment is far more critical


What exactly are you referring to with this comment? There is a displacement on the Reverse Die (Cap side being technical) that travels around the entire coin which is opposite the die fractures exhibited on the Obverse Die (Eagle side). This displacement (which has a technical name that slips my mind, is an effect caused by the alteration in pressure which results from a terminal type die fracture which has begun to displace. There is displacement of the fracture on the Reverse near the M and A in MEXICANA and I believe the die was BROKEN at this point in time and that the fragment was either barely hanging on or was being retained by the collar. Either way the displacement fractures on the eagle side would cause a change in the appearance of the opposite side of the coin.

But if you are actually referring to a WAVY or uneven area of the field - which I can not see due to a lack of perspective please let me know. An irregular surface can be an indication of a cast in a die that was finished by concave or convex polishing.

coinsnpaper Made some very good comments:




The "odd dots where they don't belong" is the critical part of the statement.

When a crack forms in a die it starts usually as a hairline split quite near the die face. Over time it deepens and widens. One of the mechanisms for a crack widening is a small fracture of the edge of the crack with the subsequent loss of a small piece of the die itself. When this happens you get a lump along a hairline crack. The dot to the right of the first A in Mexicana occurs along a hairline crack that extends through the ANA and ends at the double displacement fracture along the mid-line of the leaf.

Above the 2 in fineness I am not sure what I am seeing - there could be two points of post strike impact like two small craters OR it could be two broken surface air bubbles a clear proof of a cast copy. But I can not tell from just a picture I lack the depth perception needed.

Above the S in Peso I see a lighter spot but can not tell what it is.

I saved the comments about the dots in the dentils for last because these do in fact LOOK BAD. The area where they blend together under the date is caused by a loss of strike pressure OPPOSITE a displacement. That is not a problem but the roughness of the edge collar does require more thought. I completely agree that a pebbly surface between dentils is a way to spot a cast copy. In this case, there are other clues that point in a different direction at least to me. The collar appears to be worn. It is a piece of metal that rises and falls with every coin struck. Those actions produce wear. Partially out of collar strikes caused by planchet feeding errors also can cause damage to the collar. I do see possible evidence of chipping of the collar under the assayer initial M, and possibly under the comma in 902,7. I also noticed that the dies were not perfectly aligned making the collar margin large on one side of the coin.

I am not trying to bash anyone here. I am just trying to point out one difficult part of authentication which is focusing on one clue too much and excluding other vindicating evidence for originality.

So unless the owner has some in person observations to add which present some new information - I vote for REAL. But the coin has been cleaned and there is odd streaking (possibly carbon staining) on the Reverse (Cap) die.

fireandice556 The cracks at the perimeter would be "clues" if they were on an open sided screw press. But on an early collared strike they definitely belong.

The edge photo clearly shows standard reeding - no trace of a post cast application of reeds or of cast reeds which would have to be there if this was a cast coin. Since the edge is correct I absolutely believe the coin is real.

The dark and light streaking pattern was a problem seen on many different coins of the era and has multiple causes. Carbon spotting
from the rolling process and at times problems with the acid wash which was done before anealing of the planchet can cause the streaking. The key is that if you look at the surface under a microscope there is almost no change in elevation between the two different colors. A cast surface is irregular but looks diofferent up close. It is a textured surface.

Wow... discussions on this casting are very fruitfull information that we acquire... Thanks guys for sharing

kerjaluar Welcome to the forum.

The coin is unfortunately heavily scratched making it a "bullion" item at best, in my opinion.

However, on the picture of the edge I see what appear to be at least 12 "split reeds" - that feature always bothers me because it is usually associated with a forgery. The way most split reeds occur is when the coin is edged in a ring die. We have discussed ring dies before, but because you are new - a ring die is a tapered hollow metal die with reeds cut on the inner surface. A stack of counterfeit coins are pushed through the ring die to cut reeds into the edge of the coins. The process causes metal to flow up along the sides of the reeds and curl onto the top. Where these curls meet there is a joint (the split) at the top center of some reeds. This feature is often removed by grinding the edges which leaves another problem (but that is a different issue). By the way, I see no edge grinding evidence. A collared strike does not make reeds with a central split. In a collar the metal flows into the recess just like it flows into the recesses of the die. NO SPLITS.

I was also a bit concerned about the width of the rims and the anomaly under the date. But those could be real as easily as not.

So the coin needs to be tested to make sure it is silver and not a white metal. Have you weighed the coin accurately? If you do own a scale that can weigh to 1/100th gram you should read the threads on specific gravity and test that as well.

Good luck and once again welcome to the forum.

Also