What causes blue colored toning on 2 1/2 dollar gold coin?

bosco5041

I seen a 2 1/2 dollar gold coin in a pcgs holder that was toned with a lot of blue tint in it. It was a 1871. It was a AU-58 and I think an attractive coin but what causes the blue toning? The thread RYK posted reminded me of this but I did not want to hyjack his post about why smaller gold coins toned differently than large ones.

derryb

getting gassed by the blue PCGS label in the slab?

BillJones

The copper spots on gold coins are almost always brown, but sometimes they can be very dark brown to even black. I have seen the blue color in isolated spots on a gold coin.

I would say that what you are seeing is an unusual copper spot. Whether or not these were cased by a chemical bath the coin might have taken, as has been noted on some cents, is a possibility. I don’t know that for sure, however.

lasvegasteddy

post an image...blue on gold???

DorkGirl

I'd like to see a pic too.

Broadstruck

1871 is one of the low mintage dates and an abundant amount have full obverse/reverse proof-like surfaces.

I've seen and owned such examples and they at times come with deep orange gold and trace blueish peripheral patina.

Now if it's non PL surfaced and has blotchy blue it could possible have been treated with iodine.

Sold this in 2008 =

bosco5041

the coin I seen had an even blue tint over the entire coin.

lcoopie

any chance it's PVC?

Nic

Iodine treatment and leather storage are two.

K

BillJones

<< <i>any chance it's PVC? >>



The spots on that quarter eagle look a bit like PVC. If it is it's amazing that someone did not remove that before the coin was slabbed.

georgiacop50

You see the glaring lack of a CAC sticker?

jom

I owned this one some years ago. Thoughts?

There are also a number of modern $5 pieces with violet toning...I know Shane had one for sale a number of months ago. I think it was a Smithsonian but I don't remember exactly.

jom

CharlotteDude

Looks like it was due to long-time storage in a leather pouch. I have a '48-C QE that has purple/redish toning on both obverse and reverse of which your coin reminds me.

'dude

PerryHall

I've seen puttied gold in slabs that developed a bluish tinted milky haze over time.

liefgold

This one has similar toning to your Indian 2 1/2.

I wondered what might have caused it also.

crypto79

<< <i>I've seen puttied gold in slabs that developed a bluish tinted milky haze over time. >>



I agree with this

TwoSides2aCoin

I don't know about "blue", but I have a yellow one that triggers gag reflexes.


...it's just my photography skills, or lack thereof.