All XRF analysis are from benchtop XRF devices although surface analysis is of course skewed and the central core of a coin is more accurate to the true alloy of the coin its unquestionably gives you the alloy used. I do SUGGEST these DUROS are probably not contemporary circulating counterfeits (CCCs) or FLASA's as I have compared issues that are IDENTICAL in their dies and even their die breaks. IMO these are either low silver inventory issues in these difficult times or the dies were used by counterfeiters making these brass and bronze issues. Discussed in my new book in the Chapter on Foreign CCCs.
https://www.sixbid.com/browse.html?auction=3225&category=65694&lot=2687667 Doubt about this columnario More here https://moneditis.com/2017/02/07/reales-deaocho-varios/
8 reales Question: I often see "stretch marks" on 8 reales coins, are these due to corrosion, minting process, counterfeiting error, or just poorly struck original coins? Example below.
Mike, that is something which is called 'Plata Agria' in spanish. Translated literally: sour silver. Not an uncommon phenomena in the coining of Spanish colonial coins. It is related to improper cooling of the molten silver alloy, or to an improper alloy. Further explanation in the following link (sorry- in spanish) http://blognumismatico.com/2013/05/27/plata-agria/
Thanks Eduardo, Explains a lot, great link. Last question, does it detract/reduce numismatic value/collectability or is it a non-issue. I live in Spain and see it a good bit but have steered clear as am uncertain. Mike
Thanks for the link! I'm always looking for non-English language forum sites and sources of coin information.
Good question. For me it would depend how badly the coin is affected. For example, how extensive the fissures are, and whether they affect both obverse and reverse. In my experience, they usually only affect one side of the coin and are restricted to a relatively small area of the planchet. In this case I do not see it affecting the value much. Another important point: plata agria is considered to be proof the coin is genuine. It is thought counterfeiters would find it very difficult to fake this feature convincingly. Therefore, a coin showing this is generally considered to be genuine.
Some more reales de a ocho from Vico´s Auction https://moneditis.com/2017/03/14/algunos-reales-de-a-ocho-vico-9-de-marzo-2017-dattari/
Moneditis, That is a very nice 8 reales pillar dollar. Unfortunately, I found out about the Jesus Vico auction to late to register, perhaps next time...
@Nathan401 - could be prolonged corrosion, or could be a poorly made counterfeit. Hard to tell without seeing it in-hand and running tests. Here's my recent eBay pick-up for under $300. PCGS AU58 with currently no MS examples certified there for that date. It's probably darker in-hand than the glamour shots from their imaging department, but knowing PCGS the luster should be all there. It's in transit to me right now. Will be replacing my existing 1793 AU53 example I picked up back in 2011.
Mackat - Its a Chinese chop mark. 01mikep - Its silver surface embrittlement which is caused by the stress of copper and silver in the same alloy. I discuss this in my new book Forgotten Coins due out this summer. Its normal environmental factors acting on the coin. It has nothing to do with an improper alloy mix or other type of error in manufacturing. Could be inhibited due to annealing. On this fact still not clear to me. Nathan - agreed. Could be either counterfeit or salt water corrosion but since its a 1783 Carolus III I am 99% certain its salt water corrosion since it was THE MOST common date in the Calzador Wreck. See Robert Gurney's book on Counterfeit 8 Reales at Amazon Books to assist you in easily identifying Portrait Counterfeits with other information. At least view the Table of Contents and then decide. Good luck ... John Lorenzo Numismatist United States
@moneditis 1. What is the link to your homepage. The links to the posts above take me to only the single coins. 2. what is the name of your book? Eduard, posted: Another important point: plata agria is considered to be proof the coin is genuine. It is thought counterfeiters would find it very difficult to fake this feature convincingly. Therefore, a coin showing this is generally considered to be genuine." While this was true in the past, it is not anymore as even some crude fakes show stressed planchets with this characteristic.