I inherited this gold coin from my grandfather several years ago which seems to be suffering from oxidation, perhaps due to seawater exposure. Would NGC (for example) be able to ameliorate the effects and/or remove a significant amount of the discoloration if I were to send it in to the Conservation service, or is this a lost cause? Thank you!
If you are in Vegas or will be, I would be happy to test that in my X-Ray Spectrometer. Green and gold don't usually go together.
This coin appears to match up with the Numista listing for 8 escudos 1701-1732, KM# 57. .917 gold Weight: 26.8 g Diameter: 29.5 mm Possibly recovered from the 1715 Plate Fleet Shipwreck.
Thank you all for your replies. I was also suspicious of the color, but figured it could have been due to another alloyed metal present in the coin. The coin is 26-28mm in diameter, depending on point of measure, but is unfortunately only around 17 grams. Without an expert's opinion, is it safe to conclude that a) this is a forgery and b) it doesn't contain gold?
I hate to say it, but the weight being half what it should be tells you all you need to know. That, and the green tint. Mine looks like this. 26.8 Grams
Yeah, the weight discrepancy combined with the discoloration make the authenticity of this coin highly suspect, to say the least. It's the kind of token one might find in a souvenir shop in, oh, say, Vero Beach, Florida. From Wikipedia: The 1715 Treasure Fleet was a Spanish treasure fleet returning from the New World to Spain. At two in the morning on Wednesday, July 31, 1715, seven days after departing from Havana, Cuba, eleven of the twelve ships of this fleet were lost in a hurricane near present-day Vero Beach, Florida.
While I readily agree that the OP's coin is a modern reproduction often sold in gift shops and the like, when it come to this - - actually it does. But only under certain circumstances, and it only occurs in salt water. On shipwrecks, when silver coins become exposed to the salt water and encrustation takes place, in other words coral grows on the coin, or silver artifact, that coral takes on a black color. When the same thing happens to gold coins, or gold artifacts, the coral takes on a green color. So when a diver is working a wreck and finds blackish colored coral, he gets a bit excited because there just might be silver inside that coral. And if he finds greenish colored coral he gets even more excited because there just might be gold inside it ! I said might above because sometimes other metals, but not precious metals, can cause coral to take on the same colors of green or black. So ya never know for sure what ya got until ya clean it up. But yeah, gold and green do go together under the right circumstances.