I just bought a 25 Peseta 1880 Spanish coin -- KM#673. As usual, I weighed and measured it. It weighed 7.7 +/- 0.05 g compared to the ~8.1 g listed by Krause. I've never come across a coin ~5% underweight, even well-worn ones. The diameter and thickness measurements seem about right, and my estimate of specific gravity (assuming the catalogued .900 fineness and the rest copper) is only ~2.5% low, well within my margin of error in such estimates. Am I dealing with a phony here, or have others come across genuine coins -- particularly Spanish 19th century coins -- that are also light?
Greetings, W/O looking I'm guessing yor dealing with a gold coin. Did you have the scale "zero'd" properly? My bet is that you did and yes you've got a fake coin there Your not the first this MAY and HAS happened too. Bone
I can't speak about Spanish coins, but the most typical weight for the phony Asian silver crowns (primarily Japanese Yen and Japanese, British and US Trade Dollars) coming out of China these days is ~19-22g, while genuine weights are generally in the range of 27g +/- 1g. I agree with Bonedigger on the probability that yours is also a fake.
It should weight 8.06, so unless its an UNC coin a 0.1 g precision scale usually marks 8.0, in general fakes are from earlier types (and Spanish coins are usually accurate). Have you checked the rim carefully? If the coin was part of jewellery (an ex-mount), that could justify the 0.3 g loss. Jose
Thanks to all who replied, especially josemartins. My scale is well calibrated, so the 7.7 g is accurate. But I now see by very close inspection of the rim with a 10X magnifying glass that there are silvery (solder?) marks at points along the edge, so it probably was part of a piece of jewelry. I would have thought that would make it heavier. Are you suggesting that the rim was abraded at the solder points in making the jewellery? It is true that around those points the original rim markings are gone.
George, For the coin losing about 0.3g, i was actually thinking that the rim was partially removed all the way around to be in some kind of ring or hoop. That is hard to notice unless you've got another 25 pesetas coin (or a scale...) Jose
Reply to GDJMSP and josemartins Thanks again for your valuable comments. GDJMSP: I would insert the pix, but they seem to have too many bytes for the upload manager. You can see them on the eBay listing at: cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=8344224250&rd=1&sspagename=STRK%3AMEWN%3AIT&rd=1 (I tried to upload the url with the url-upload button, but the resultant inserted url had some parts deleted, so clicking on it led nowhere. You'll have to copy the above and paste it into your browser, then preface it with http://) Josemartins: The abraded parts of the rim are about one-third of the circumference. The rest of the rim seems unabraded, with original die markings. I plan to return the coin to the seller, who seems an honest enough guy.
Here's a link to the auction - LINK I'm not familiar with these, but it does look like it was perhaps mounted as jewelry in a bezel. And if that was cut or ground off as josemartins suggested - that would explain the coin being underweight.
