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red spots on gold buffalo
myth
Posts: 280
I just looked at my 2006 and 2007 proof buffalos, and they have seemed to develop red spots. Anyone have info on what this is from?
I will posts pics soon, if I can get the detail to show them.
I will posts pics soon, if I can get the detail to show them.
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Comments
Eric
Just kidding.
Keep an open mind, or get financially repressed -Zoltan Pozsar
Not copper but rather copper-silver alloy.
John
Never view my other linked pages. They aren't coin related.
Red plague sounds like something from the cold war.
<< <i>Disagree. Copper doesn't turn red but corrodes as a blue green. Buffalos have a copper silver alloy in addition to the gold. Silver and copper can create a corrosion product called "Red Plague" That's what you've got. Likely, during the alloy process something didn't quite go right.
Not copper but rather copper-silver alloy.
John >>
I don't think gold buffalos were alloyed. You may be thinking of AGE's.
Worry is the interest you pay on a debt you may not owe.
<< <i>Disagree. Copper doesn't turn red but corrodes as a blue green. Buffalos have a copper silver alloy in addition to the gold. Silver and copper can create a corrosion product called "Red Plague" That's what you've got. Likely, during the alloy process something didn't quite go right. >>
Really?
<< <i>John is correct.... red plague.... Cheers, RickO >>
Does it look like this??
Read this!
K
<< <i>Disagree. Copper doesn't turn red but corrodes as a blue green. Buffalos have a copper silver alloy in addition to the gold. Silver and copper can create a corrosion product called "Red Plague" That's what you've got. Likely, during the alloy process something didn't quite go right.
Not copper but rather copper-silver alloy.
John >>
I am not familiar with the "Red Plague", but the impurities in the gold can indeed result in red copper spots. It is not particularly uncommon.
John
Never view my other linked pages. They aren't coin related.
<< <i>Buffalos do have a silver copper alloy as do the AGE's. If they were pure gold they'd be way too soft and easily damaged. >>
Gold Buffalo's are 9999 fine gold and have NO added alloy.
Worry is the interest you pay on a debt you may not owe.
<< <i>
<< <i>Disagree. Copper doesn't turn red but corrodes as a blue green. Buffalos have a copper silver alloy in addition to the gold. Silver and copper can create a corrosion product called "Red Plague" That's what you've got. Likely, during the alloy process something didn't quite go right.
Not copper but rather copper-silver alloy.
John >>
I am not familiar with the "Red Plague", but the impurities in the gold can indeed result in red copper spots. It is not particularly uncommon. >>
Mark,
Copper in the presence of gold will either create an invisible film or turn blue green. The gold that comes out of the US mint is alloyed with a copper-silver alloy. This is where the red spots come from.
Not uncommon for other coins to contain multiple alloys. But rest assured copper does not turn red. Ever. It's the galvanic reaction between the copper and the other base metal (silver) in the case of the Buffalo or AGE. As for the copper coin somebody else posted which is red its same same although I have no idea what the alloys are in that coin but having taught Corrosion Science for many years I can tell you its not just the copper doing that.
And to some extent it goes way beyond that as well. The oxide films that form can react with certain environments to do all kinds of goofy things. Depends on the oxide film and what electrolyte it is exposed to.
John
Never view my other linked pages. They aren't coin related.
<< <i>A couple of the gold buffs I have also have the red spots. The funny thing is that they were there when I received them from the mint, not days or weeks afterwards. The spots are a dark red, sort of like a paint droplet or ?? Since I bought them mainly as bullion not a big deal...one of the spots is on the obverse indian head and it looks like he has a cut on his face.
K >>
Yep, that's exactly what I've seen as well. It's as if someone took a red felt pen with an extra fine point and made a single spot. Mine came from the Mint that way. I've only seen it on buffaloes, never on gold eagles or first spouses.
<< <i>
<< <i>Buffalos do have a silver copper alloy as do the AGE's. If they were pure gold they'd be way too soft and easily damaged. >>
Gold Buffalo's are 9999 fine gold and have NO added alloy. >>
Then explain the red spots because gold does not corrode red.
A 24 karat designation can be had in some parts of the world by having a 99.0% gold to 1% alloy ratio. I think the larger question to the Mint should be....."Why is my .999% gold coin exhibiting corrosion products formed from copper and silver.
Without a doubt if your gold coins are spotting red, there is an alloy. The content may be minimal but there is an alloy.
There are different "kinds" of gold as well. Depends on where it comes from.
John
Never view my other linked pages. They aren't coin related.
<< <i>But rest assured copper does not turn red. Ever. >>
Again... Really?
"I had an 08w pr70 PCGS $50 Buffalo that developed a half dozen red spots-sent it in for spot review and it came back as new.As of today its been close to 4 months with no recurrance."
Is it possible that PCGS gave you a different, perfect coin in return? It's not like PR70 buffalos are hard to come by.
Keep an open mind, or get financially repressed -Zoltan Pozsar
<< <i>Then explain the red spots because gold does not corrode red.
...
Without a doubt if your gold coins are spotting red, there is an alloy. The content may be minimal but there is an alloy.
>>
One explanation is that there is some surface contaminate that is turning red -- it may not be the copper or copper/silver and the alloy may have nothing at all to do with it.
Color me doubtful...Mike
<< <i>
<< <i>But rest assured copper does not turn red. Ever. >>
Again... Really?
Do you think that coin is 100% copper?
Never view my other linked pages. They aren't coin related.
Worry is the interest you pay on a debt you may not owe.
<< <i>
<< <i>
<< <i>But rest assured copper does not turn red. Ever. >>
Again... Really?
Do you think that coin is 100% copper? >>
Of course not.
Is there such a thing as 100% copper? Even more to the point, do we call them "copper" or "copper/nickel/silver/gold/etc." alloy?
While it may be technically correct to call the red areas "copper/silver" spots (and I'd wager there is more than just silver and copper and gold in the alloy), even alloys that are primarily copper and commonly called copper do corrode red as evidenced by the coins posted in this thread, and (IMO) they are correctly called copper spots.
Have a nice weekend...Mike
<< <i>While it may be technically correct to call the red areas "copper/silver" spots (and I'd wager there is more than just silver and copper and gold in the alloy), even alloys that are primarily copper and commonly called copper do corrode red as evidenced by the coins posted in this thread, and (IMO) they are correctly called copper spots. >>
Correct. There are more metals in alloys generally. And don't forget inclusions from carbon as well. I do disagree that red corrosion products should be called copper spots, though. I spent way too many years in the US Government training Navy personnel in Aircraft Corrosion Control, I guess.
At the end of the day you call it what you want, I'll call it what I want, and I'll buy the first round.
John
Never view my other linked pages. They aren't coin related.
Reopening this thread, as I've picked up a few Buffalos just for fun.
Two have those tiny red dots, while another has a totally mottled appearance, with a darker shade overtaking the obverse, a bit like kudzu taking over a forest.
These are all graded 70 by our host. Should I be doing something about it? Are these no longer 70s?
Can you please post some Images?
“I may not believe in myself but I believe in what I’m doing” ~Jimmy Page~
My Full Walker Registry Set (1916-1947)
https://www.ngccoin.com/registry/competitive-sets/16292/
Not much you can do. Spotting happens. Whether impurities or copper, the bottom line is the same.
Are they still 70's? I guess you could assert they are if the holder says so. But buyers may feel otherwise.
Lance.
I do not think buyers will treat them as 70's.... A post above says they can be removed... or the coin may have been replaced.... I would send them in for 'conservation'.... Cheers, RickO
Sorry, no time to read all of this but I'll post some of the stuff I learned in a coin conservation presentation.
The gold coins we are talking about are certainly .999; however they will spot - mostly a reddish copper color. These spots look and act identical to the spots that can appear on all our gold including vintage .916 fine. I don't recall their chemical composition. Who cares - we call the spots "copper spots."
Under high magnification there are two types of spots. The first - mostly on our modern gold coins seem to be stains on the surface. The stains can be all shapes including tiny round spots. If you know how, they come right off in a matter of seconds.
The second type are "reaction rings" that are caused by something into or on the surface of the coin. On our vintage gold there is usually a tiny impurity struck thru somewhere near the center of the color. While the copper colored "ring" can be removed easily, other techniques are used to remove the debris when necessary.
The spots and copper stains show up as a reaction to the environment. Take a look at some of the "before conservation" gold treasure coins with reddish stains from submersion. Yeah, yeah, gold does not corrode but it sure does stain.
Since these spots and stains are detracting (eye-appeal), they will lower a coin's grade.
PS Decades ago, copper spots on gold were a good indication the coin was genuine. Today, they can sometimes be found and counterfeit gold - like Pandas.
PSS One thing I hate is when someone (no matter how expert) comes into "MY HOUSE" (numismatics) and tries to change OUR terminology. All it does is cause confusion and highlights their possible lack of understanding. I suggest these folks learn a few things about "the territory" before they post so their opinions come down to my less knowledgeable level. We call them "COPPER SPOTS and STAINS."
PSS We were talking about gold and someone posted some OFF TOPIC corrosion on Large cents to make a point. Copper corrosion products come in many colors. Black, white, green or red are common. Green and red are the active one's. White is usually a place where overlying green corrosion was disturbed.
Bravo!
Surface contamination at some point...maybe production, or packaging or post-Mint handling if removed from the original packaging.
Given the fact that these coins are supposed to be .9999 gold, the fact that they have red spots is not a good thing. This has shown up in prior years. It has to be something the mint usese to clean the planchest before they are struck.
The spots are not from the coin alloy - they are from particulate contaimnates landing on the coin.
I have heard that copper spots are easily removed if not sealed in a plastic holder.
Buffalo Pox.
This was my coin. It started to turn and continued to show up in other parts of the coin. I think it was Mint Employee Contamination.
They should come off w/o a trace. I would not touch the coin anyway. by the time you sell it, the price of gold will probably cover the cost of professional conservation.
Thanks to all!