Well, here we are about a year and a half after I got my 2016 Standing Lib quarter straight from the mint release. Has never been out of the plastic capsule and has been stored in an intercept slab holder inside an intercept box for most of that time. And yet, a bright red spot has developed on it right above the shield and below the E in the field. It's like a blotch of ink has appeared. It is bright red. A speck about the size of a rivet on the shield. Was not there when I got it. Being 24k gold, what on Earth could have caused this? Has anyone else seen any spots develop on their sets? My merc is ok. Was looking at it because wanted to send it in to get graded but I'm sure a 70 is out of the question now.
This coin is 0.9999 pure gold. What that means is 0.0001 is other stuff (silver and copper, mostly). The copper will sometimes tone. You see this far more often on older coins where they were 0.9000 fine gold, so there was a lot higher concentration of alloys. This is called a "copper spot" and is perfectly original and natural - although it is considered a blemish on modern coinage. Nothing you can do about it, really. Once it appears, you can treat it and temporarily remove it, but it will return.
Copper composition bleed through https://www.cointalk.com/threads/copper-showing-in-gold-coin.101076/#post-2953268
This coin is 0.9999 pure gold. What that means is 0.0001 is other stuff (silver and copper, mostly). The copper will sometimes tone. You see this far more often on older coins where they were 0.9000 fine gold, so there was a lot higher concentration of alloys. This is called a "copper spot" and is perfectly original and natural - although it is considered a blemish on modern coinage. Nothing you can do about it, really. Once it appears, you can treat it and temporarily remove it, but it will return.
I have heard of copper spots but never expected it would happen on a 0.999 just because there's so little else in it. The few old 90% ones I have still look like new. I read an article by NGC in 2009 claiming the spots should not have an affect on the grade. Do we know for sure if it's removed that it would come back? I just saw one on ebay that has a couple big black spots on it. Covering the head and one on the shield. Guess it was luck of the draw who got what.
Some folks prefer or don't mind a copper spot or 2 because it shows it's an authentic coin like the $20 saint and others. On the saints and other U.S. coinage that are .900 pure they also have carbon/copper spots. I personally love the 3 coin set... Gold Mercury., Gold standing quarter, And the gold walking half. Mine are graded pcgs-70's. Hopefully they don't aquire the spot(s). But, If they do, No worries here. I know where i purchased them. From a very reputable company.
There is no guarantee either way. I don't know about the modern coins, but I know on the older stuff that when spots are removed, they come back more often than they don't. I would assume it would be the same on this.
I have received differant Gold Euro coins and received one with the little red spot. wrote back to the dealer and was told that that does appear on some .999 gold coins. had me concerned at first.