Question on Acid Testing for the resident experts

cdv1

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Jun 29, 2011
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So today I get this little yellow chunk of metal in my scoop (small pendant from a necklace) that has the right color, has some weight to it for its size and everyone thinks it is the real McCoy..... I get home, check closely for markings and there are none so out comes the test kit. Now I've used it before just for practice but here is what my results are: Scratch the item on the stone and get a good line on the stone. Check the item where I scratched it to see if I see a different type of metal under the gold color.... nope, it seems to be solid and not plated (I really scratched it to ensure any plating would be worn off just in case) Now I put three drops of acid on the stone (10k, 14k, and 18k acids).... 18k immediately dissolves the gold.... 14k still shows gold and so does the 10k.... so since I'm now sure it is gold, what k value is it?

I had the same results the other day with a partial grill I found but I know they do use 16k in some dental gold. I assumed that jewelry didn't come (here in the states anyway) anything but 10, 14, 18, 22 and 24k....

So, am I doing something wrong or should I feel confident that the piece is at least 14k?

Cliff
 

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The acid has shown it is at least 14k, but less than 18 k.
If line disappears it means it fails the test for that grade of gold.
 

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Treasure_Hunter said:
The acid has shown it is at least 14k, but less than 18 k.
If line disappears it means it fails the test for that grade of gold.

Treasure hunter is correct. You most likely have 14k, in the states you rarely see much that falls between. In fact when you go to sell, the same test will be preformed and they will get payed out at the 14k rate (approx. .583 x weight in Troy Oz X current price of gold per Oz).
 

Thanks guys that is what I thought.... just don't get alot that isn't marked.

Cliff
 

You should test everything that is marked too, as not all are real gold. But Treasure Hunter is right.

Some jewelry makers use the same mold for other metal rings too as these aren't stamped but in the mold itself.
 

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You should test everything that is marked too, as not all are real gold. But Treasure Hunter is right.

Some jewelry makers use the same mold for other metal rings too as these aren't stamped but in the mold itself.

Thanks Sandman.... I'll make a point of it from here on out....could be interesting!

Cliff
 

This is is really from the buying side but woks both ways. Genrally we use only 14k acid to test 10k & 14k gold,that is stamped.Because 10k acic is really diluted and if not giving enought time you could get a false reading with 10k acic.If you think its 10k and use 14 acid the scratch will turn a nice brown before disapearing in a few seconds.If its 14k it will not turn brown and it will hang in and not desolve quickly 15 seconds, if it never starts to disolve it could be a higher carrot.But in the case of marked gold the stamp superseeds acid test. When buying we are never concerned with mistakenly buying 18k thinging its 14k.
Now when its stamped 18k its a different ball game. Lots did I say lots of 18k in the United States right now is Stainless Steel. This will pass an 18k acic test everytime. Three ways to check is first it has to feel like gold when you scratch it, it should not drag, gold is soft. .If it does suspect SS. Test at 18k then at 22k if it passes both its not 18k. It should seem the right weight for size.Unmarked gold will respond the same way but you clueless before the test as to what to espect. Remember back in the 80's they were allowed to mark jewerly 14k and it was only 12.5k and it was leagle to do so. Also acic goes bad so replace it frequently.
Hope this helps heres a nice page.
Precious Metal Testing
BCNJ
 

between 14 K and 18.
Sandman is right about checking your marked rings.
I have allot of older gold rings that are marked but test a caret or few higher.
Maybe back in the day gold was fairly cheap and they didn't skimp on it?
 

This is is really from the buying side but woks both ways. Genrally we use only 14k acid to test 10k & 14k gold,that is stamped.Because 10k acic is really diluted and if not giving enought time you could get a false reading with 10k acic.If you think its 10k and use 14 acid the scratch will turn a nice brown before disapearing in a few seconds.If its 14k it will not turn brown and it will hang in and not desolve quickly 15 seconds, if it never starts to disolve it could be a higher carrot.But in the case of marked gold the stamp superseeds acid test. When buying we are never concerned with mistakenly buying 18k thinging its 14k.
Now when its stamped 18k its a different ball game. Lots did I say lots of 18k in the United States right now is Stainless Steel. This will pass an 18k acic test everytime. Three ways to check is first it has to feel like gold when you scratch it, it should not drag, gold is soft. .If it does suspect SS. Test at 18k then at 22k if it passes both its not 18k. It should seem the right weight for size.Unmarked gold will respond the same way but you clueless before the test as to what to espect. Remember back in the 80's they were allowed to mark jewerly 14k and it was only 12.5k and it was leagle to do so. Also acic goes bad so replace it frequently.
Hope this helps heres a nice page.
Precious Metal Testing
BCNJ
thanks everyone, good info to have
 

White gold and 18K are real tough to test. Make sure you're not scratching the stone. Gold is soft and is kind of like chalk on a chalk board when you rub it against the stone. Like what was said before, use a higher K acid and the mark should go away. You can use a small file to make a small relatively deep cut (enough to get through any plating) in the piece (if you don't care about it) and put the acid directly in the cut. Look through a loupe and if it bubbles up it's fake. If all else fails take it to the pawn shop and ask them what they will give you for it.
 

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