When I noticed the splotches, I took this coin out of its transparent blue sealed mint sleeve thinking they might have been on the plastic. I bought this coin from a major bullion dealer so I believe it is genuine but wonder what has caused the discoloration. Anyone know?
I had something similar happen to a 1925 double eagle of mine; slabbed by NGC as MS-61, so clearly genuine, but not the most attractive visually.
Yeah, but your double eagle had copper in the alloy, that can happen. The OP coin is supposed to be .999 pure gold, so there should never be copper spots. With the spots showing, it sure LOOKS like its a fake that has another metal under the gold coating.
Yeah, I'd be alarmed seeing that on .999 -- it's possible that the bits of foreign metal left in the gold could concentrate into spots that tone, but it seems really unlikely. Now that you've taken it out of the packaging, have you checked its weight and dimensions?
Do you guys see what I do though? Look on his face. It looks like a core is showing through the gold. In a couple of other places as well. Chemicals on the surface wouldn't produce THAT.
https://blog.goldeneaglecoin.com/red-spots-gold-coin/ I found the above, the splotches on their image look like the ones on mine.
https://forums.collectors.com/discussion/1040053/pcgs-results-the-good-the-bad-and-the-ugly If you look at the gold standing liberty quarter there the spots look very similar and the mint says those are .9999 gold While the OP coin could be fake, the spotting does happen
I wonder what the bluish-silver in the center of the red blemish is and is caused by. If the coin was supposed to be .9999, what impurity is this? Are the planchets truly as pure as advertised?
Wow, sure enough. Sure wish someone could go after a couple of these with a high-res, tiny-spot-size XRF setup. Or sacrifice one for destructive analysis. But for all I know it's already been done. If @Insider says they're easily treated, that sort of implies knowing what they are.
Fair enough. I like to learn something new. However, these coins are sold as .999 pure. Any idea of what these impurities are? Do you think the planchets are pure but the impurity contaminates them at the mint? .999 does not seem to imply any possibility that the impurity is in the planchet, unless .999 is incorrect. Is the bluish-silver dark spots in the middle of the spots the metal imperfection? Any idea what it is?
Have you seen enough to say whether these spots tend to be stretched out and parallel (indicating that they're in the stock before it gets rolled)? If these coins can be conserved successfully, is it possible this is foreign matter on the coin's surface, rather than something from the alloy?
"I took this coin out of its transparent blue sealed mint sleeve " Every gold coin I have purchased from the Mint was in a plastic round I have never seen a Mint coin in a transparent blue sleeve.
You'll need to remind me to post images at a later date. No matter what the fineness is, "copper-colored" spots appear on gold straight from the Mint or they develop over time. The common explanation is they result from an impurity in the ally mix near the surface that reacts with the atmosphere. I don't know anything about them except for this: There are two basic types. A spot on the surface that comes off w/o a trace and a spot that is actually a reaction patch surrounding a tiny black chunk of debris struck into the coin. As you can see, purple and blue are also associated with the copper and reddish colors.
If it's just a very small surface inclusion, or a surface layer a few atoms thick, I think you'll have a hard time getting useful info out of one of those guns.