1718 Spanish 8 Reales - Twins Or Not

I'm unfamiliar with these coins, so I'll ask for clarification.
If these are two different coins, why does the flan have a similar shape/defects?
Some details match on both coins (dark arrows), while others seem unique (light arrows)
Again, just asking to learn something here.

DVCollector You have one of the answers which leads to the others.

The two coins share both identical and different post strike damage - your white and black arrows. Your nice photo saves me the time of doing the same thing.

These two coins are DIFFERENT copies made from the identical molds. So they are TWINS not the same coin.

Because they are made by casting with a transfer image mold (a high quality one) the coins are FAKES - they are not counterfeits however.

They are Numismatic Forgeries. The value is therefore theoretically melt. In my case I go $15 over for new examples for my collection.

This is precisely the type of information that we used to use at ebay to get an ebay member permanently suspended.

tokenmast The post mold damage are the actual differences between the two coins (white arrows) that makes each unique. The black arrows mark damage that is present in the mold and appears on all examples. The reason there is damage in the mold is that the master image has damage itself.

A mold can of course be offset simply by placing the master image in the mold matrix off center. Molded coins can also have die breaks, planchet clips, chop marks or any other feature seen on a coin.

On the shield side note the cut in the dentils near the P. On one copy it is clear and deep on the other there is just a hint. There are also differences in letter thickness.

Those copies are impressive, particularly the last one which sold for much !
I would have gladly checked that one in hand ...

I checked my catalog, I don't have any from this period to compare with (the closer is Sevilla 1730 - which uses another design, and has a good chance of being genuine as it came from the HSA collection) ...
But with the two pictures side by side, it's clear there is a problem (the other side is even easier, with a very visible post mold blow)

Bob : I'll repost them to the Facebook group, they are an excellent learning tool - thanks ! Those with an account there ... please don't give it up too fast, I'll post the first coin, then the other one (I'd like to know if someone see something on the expensive one - I was unsure about the design but didn't figured out that it could be wrong).

Cool thread!

Robert : here is the genuine coin used to make the mold
http://www.acsearch.info/search.html?id=818211

Now, I was wondering ... seeing that one of the coin is wrong was well explained (damaged on both, but additional damages on one of them). The second coin didn't had "white" (or another color) arrows to show missing damages from the other coin.

What makes you think this was not the original ?
Actually, the patina (if you ommit the picture style) could match on the cross side. (well, the pearls on the other side, on the crown, don't seem to match ...)

MathieuMa I am suspicious of both of these because of a third example that appeared on the Sedwick site. The patina of the two coins on this site clearly means neither of these two match the third yet all three show numerous examples of post strike damage that are otherwise identical.

Now that I have seen THREE IDENTICAL copies I will not say any of the three is genuine without conclusive scientific tests on the coins to discover a "unique" genuine trait seen on only ONE exemplar.

MathieuMa The two coins you show are not the same coin - are you maintaining that they are?

Look at the shape of the chip near the S in Hispaniarum - it is not the same on these two coins even taking into account cleaning and lighting. A close look at many features indicates the same thing. There is also a scratch outside the ring of dentils near the M adjacent to the damaged dentil that appears only on ONE coin. There are many other smaller indications like the size of the dots on the crown at the right side near the rim or the damage to one of the joins in the double border line nearest the X in REX. Taken together I see a real concern that these are only the tip of the iceberg for this particular issue.

These are all coins cast from the same mold or a series of molds made from one master. They are likely casts in silver - but I ask has the density been checked in any case? Does the auction site where one of these two coins appeared have a record of the density? Or was it passed because it "looked" right? I suspect that any of these coins might pass the "looks right" test if seen in isolation.

However, now we know that regardless of how many of these were made that all but ONE example are FORGERIES. Perhaps the original if one existed is still in the forger's collection.

Having discussed modern forgery techniques with many experts (including active forgers as well as die makers) I know that cleaning of the type being postulated does not have to occur at all. The coin does not in fact have to be cleaned to produce a mold using many forms of dental plastic molding. Some techniques I will indicate do absolutely require cleaning especially those involving electro-chemical means. But to presume that the coins are identical and therefore one of those particular two must be real simply because it appeared in an prestigious auction is not credible. I have purchased many counterfeits from similar venues.

The coins I class as counterfeit are those that fail to pass scientific tests - primarily SG tests.

Yet I know of NO auction house that screens coins using SG testing and NONE that posts the SG of the coin in the auction data. You are quite frankly lucky to get an accurate weight.