Fake gold or real? How to test your gold.
Here a few tools, techniques and tricks on recognizing real gold. Sadly, gold hallmarks are not 100% reliable, with unscrupulous people adding false ones especially recently. I've had a lot of experience and still, very rarely, I have been fooled so you do have to be careful and thorough...
There are many ways to test for gold purity, ranging from mass spectrography (you need a university in your pocket for that), refining (you need a furnace), various electronic testers (too expensive unless you’re a professional) or you can buy a few acid solutions and a touch stone from your local jewellers supply.
This is what I have used over many years and it has seldom let me down. You cannot buy these online as they are very powerful and dangerous acids and shipping these by mail is banned and please be careful when using them. Disposable gloves are a must unless you want yellow stains on your hands that will stay their until the affected skin comes off. That's not a joke.
TOUCH STONE ACID TESTING...
The acid solutions are marked with various karat gold strengths, usually 9K, 14K and 18K. This is in Australia. Other countries have their own standards.
You must have samples of known ct / K gold to compare with if you use the touch stone method. A touch stone is a ground black glass sheet or similar.
You take your unknown piece and rub it on the touch stone leaving a mark. You then rub your various known carat golds next to it and apply the acids across them all. The unknown gold will react the same as one of the known gold marks (generally the mark disappears). And thus the unknown becomes known.
I personally use the next method as it is far more accurate and reliable although it will leave a permanent mark.
ACID TESTING THE ITEM DIRECTLY...
Because you are only rubbing surface gold onto a touch stone, you may not be testing what’s really inside. It may be just thick plate. What you need to do is go through the surface of the gold by using a file or blade in an INCONSPICUOUS place. A good place in the case of a chain or bracelet is to do it inside the links or clasp, where there is already a lot of wear from links rubbing. File or cut into it a small amount and then place a drop of, say 9K acid, directly on the cut...
- If no reaction then it is at least 9K.
- Use the next highest acid (say 14K).
- No reaction then try 18K acid.
- No reaction? Then you know it’s a least 18K gold.
- Some of the reactions you may see are as follows...
- If the cut goes brown then it’s gold but less than you acid strength. Try a lesser acid until no reaction. That’s your carat gold.
- If it goes green and may bubble, it’s got copper in it and is plated gold. Copper is nearly always used in the gold plating process.
- If the acid goes milky white and the metal black, it is possibly silver.
- The only reaction you want to see is a brown tarnish on the gold….All else is NOT solid gold.
Remember you want to test well below the surface. I have seen many old pieces of jewellery that have many nicks and file marks having been tested numerous times. Sadly some dealers are none too subtle as to were they mark the piece. If you think about where to test, you should leave only an inconspicuous mark.
Things that should raise your suspicions...
- Look for discolouration. Plating wears and the metal beneath may show. Inspect between the links and near the clasp where the piece rubs the most. If in doubt, test.
- Anything lacking known hallmarks should be questioned. There are a number of reasons that the marks may not appear. The piece may have been repaired. A ring may have been resized. A piece may be worn enough to rub away the hallmark. If in doubt get an unconditional guarantee and then test.
- Experience in the colour of particular carat gold is important. 22K or 24K is a bright bright yellow. 18K is a strong yellow. 14K is less and 9K less yellow again. Not always a perfect indication as sometimes a lower carat gold is plated with a higher carat gold to make it look better. That’s not illegal.
- Look at the links. Nearly all gold jewellery has every link soldered closed. Gold is a precious metal and no self-respecting jeweller would leave links open so you could lose the piece easily. If any link is unsoldered be suspicious
- Most fake gold chains and bracelets are heavy. Lightweight counterfeit are uncommon. That’s because it’s only worth forging heavier pieces. No point in breaking the law for peanuts.
- With rings it’s a different matter and you have to be particularly careful and of course if the piece discolours your skin then you know it’s not gold. To late, then, I'm afraid.
Many other tests only come from experience. A few are a bit strange but are enough to raise your suspicions.
- Gold is a very heavy metal and over the years you learn the “feel” or “heft” of it. I can generally tell if it’s ok by the weight as it falls into my hand.
- Gold is a soft metal. With high karat gold (22K, 24K) you can leave a mark with your teeth. I’m sure you’ve all seen it on TV. It works but don’t try it on 18K or less if you value your teeth.
- Many have suggested a magnet is a good test. I have yet to encounter gold plated steel jewellery so I don't think that test has much use. In fact I have never bothered with it.
- An interesting one is the smell test. When people say they can smell gold they may not be far wrong. If your hands are sweaty, rub the gold jewellery vigorously in the palms of your hand. If it’s plated you may smell a strong acidic metal smell. That’s the electrolytic reaction of your salty sweat on the plated metal.
- In the old days people were able to recognize the “ring” or “tone” of a gold band which was tied to a hair and tapped.
- None of the last few can be relied upon and are mentioned out of interest.
So the best thing is to buy a gold testing acid kit. They are not particularly expensive, considering the price of gold. It will have full instructions. Next, make sure you get a guarantee as to the gold you are buying. Check it yourself if you feel confident or have it checked by a professional.
One last point worth making is that if the piece of jewellery has some age, and the hallmark is clear and in the style of the period, you can be pretty cetain the piece is genuine. It seems only more modern items are sometime less reliably hallmarked.
LASTLY, I point out that I am not a jeweller and that the above guide is just that, a guide. I am a pawnbroker with 25 years experience. If you want professional advice go to a jeweller.
SEE MY OTHER GUIDES FOR OTHER INFORMATION ON JEWELLERY. Vote as appropriate.
© 2008 Edward Vabolis