Gold testing

[Drosera]

I have a question for those of you familiar with testing gold. I know that the acid test kits come in various increments meant to test for 10k, 14k, etc. but I'm not sure what happens if you test a ring with a higher level test kit than what you expect the ring to be. Since that sounds confusing let me tell you what happened:

I found a ring that is marked 12k. To make a long story short I brought it to a jeweler and they used a 14k test kit and told me it wasn't gold. If it really was 12k gold would it have shown positive on a 14k test?

For those interested in the background on this. I found this ring in the same hole as a 10k ring that is definitely gold. The weird thing is this 12k ring was brown just like oxidized copper. I assumed it was junk because of the color until I found out that one form of 12k gold is 50% gold 50% copper. I figured that if it sat in the ground for 10 years or so the copper might react and turn brown masking the gold.

I know it is more likely that this was a gold plated ring that shed its gold coating leaving only the copper base behind. But I want to make 100% sure it is junk before relegating it to the junk pile.

[Cfmct]

Show us a picture of the ring... as to whether the gold will hold at 14k if its a 12k ring most likely not... if it doesn't hold with the 10k solution then the ring is probably a fake...

[steve in so az]

If a ring is 1/2 copper it surely cannot be 12 K gold. Also, if a 10K ring is acid tested with a 14K acid it will not show as gold as it is not 14K. But if you use 12K acid tester it will show as 12K . If not, then it isnt gold. Or at least not 12K. steve in so az

[steve in so az]

Also, over the years I have dug a few brownish rings that proved to be 14K. They came from the chip bark which exudes tannic acid. Steve

[Dustyloins]

Originally Posted by steve in so az

Also, over the years I have dug a few brownish rings that proved to be 14K. They came from the chip bark which exudes tannic acid. Steve

Ditto.

Dusty

[Drosera]

Here is a picture of the ring I'm talking about. I found it in a hole with a 10k ring (same size so I'm sure they were lost together). The image on the left is the 10k ring, the one on the right is the one in question. I should note that the ring I'm talking about is dark brown, but my pictures make it look more of a greenish-light brown.

Steve,

Why do you say it can't be 50% copper? I was at the LA museum of Natural History this weekend and they have a big display on gold (because of its importance in CA history). They have a section that explains what the different karat levels mean and show some actual examples. One of the displays is 12k gold and they have one sheet that is 50% gold/50% silver, and the one right next to it is 50% gold/ 50% copper. That is what got me thinking this might be real. Regardless of what the actual composition is I figured that if copper makes up a large portion of the ring it could corrode even if gold wouldn't. Though this being a gold plated ring that lost the gold plating is more likely.

[steve in so az]

Companys can make up any kind of gold mixture but I believe the govt regulations say only a very small amount of non gold for hardness can be used if it's to be commercialized. Steve

[waynegohl]

this is very interesting.

we have a guy that buys our old gold (broken and odd pieces) and he has a liquid he pours on the gold and it either changes color or it does not. what is this liquid he uses and will it work differently on 9ct and 18ct gold?

[RickO]

Steve, I think the only regulations are that the gold content must be stamped on the item - i.e. 10kt, 14kt, 18kt etc. A 50-50 mixture of gold and another metal would be 12kt. 24kt is pure gold (at least .9999). RickO

[Rudy]

Originally Posted by steve in so az

Companys can make up any kind of gold mixture but I believe the govt regulations say only a very small amount of non gold for hardness can be used if it's to be commercialized. Steve

I think the regulations in the US is in respect to the minimum karat which can still be called gold. In our case it is 10 K. In the UK, I think they can go down to 9 K but I'm not sure.

[steve in so az]

R & R - probably so - I stand corrected, Steve