How to Test Gold at Home or When Traveling

In previous blog posts, you have learned the difference between a karat and a carat as well as understanding the karat value of gold.  But how can you test gold to find out if it’s real or not?  And how can you be sure the karat number that’s imprinted on your jewelry is authentic and not a fake?

There are several things you can do to determine whether that piece of jewelry is real gold, and what the karat value is.

The Magnet Method

Before bothering with the following gold-testing methods, take a high-strength magnet and touch the gold item you want to test.  If the item is strongly attracted to the magnet, it probably isn’t worth the effort to test.  If the item is slightly attracted to the magnet, continue with one of the testing methods.

Acid Testing

CAUTION:  Although this is the standard way of testing gold, it does include the use of corrosive acids.  While it can be safely done, take the necessary precautions.  Cover your work area with newspaper and don’t put extra jewelry on it in case some of the acid splatters.  Wear protective goggles and rubber gloves.

If acid should splatter on your skin, wash it off immediately with large amounts of water for 15 minutes, and then put baking soda on your skin or cover it with an emollient.  For complete precautions, see the Material Safety Data Sheet on hydrochloric acid, which is a PDF file.

Read the instructions carefully in the test kit.  If you have a grey stone, it needs to be heavily-sanded first and then covered with acid from the 14K squirt bottle to prep it.  If you have a black stone (which most of the kits now have), you’re good to go with no prep work.

This method combines the use of a smooth testing stone and several droppers of nitric acid, or nitric and hydrocholoric acid for higher karat levels, each designated to let you know how many karats the gold is.  The premise behind this is that pure gold is unaffected by strong acids whereas other metals are highly reactive.  In Understanding the Karat Value of Gold, you learned that gold is combined with other metal alloys to make it stronger, and that the fewer the alloys the higher the number of karats.

When you rub your gold jewelry on the testing stone, push on it a little so you’ll be sure to leave tiny pieces of gold on it.  If you’ve done it right, you’ll see a streak on the stone.  Next put one drop of nitric acid (which comes in the acid kit) on the streak.  For example, if you use the 14K dropper, the streak’s color won’t change at all if it’s 14K or higher.  The acid test will also tell you if your item is made of gold or is gold plated.  

NOTE:  When you rub the item on the testing stone, locate a small inconspicuous part of your jewelry such as the edge of the necklace or ring so you don’t risk hurting the item. 

Electronic Gold Tester

If you want to learn more about your gold items so you can sell them, or want to buy gold at flea markets or garage sales or estate sales or when you’re traveling, you can buy an electronic gold tester.  They are small battery-operated devices that are easy to use with a mild testing solution. 

Using this method, there is no need to rub the gold item on a stone and use acid to find out what the karat value is and whether an item is gold plated or solid gold.  (Although there is a controversy over which method is more accurate:  electronic gold testing or acid testing.)

RS Mizar offers three electronic gold testers.  The RS MIZAR M24 GOLD TESTER TESTS 9K-24K PLATINUM quickly will tell you the karat value, 9K-24K.  It detects platinum and tests all colored gold. 

There are two less-expensive versions.  The MIZAR M18A9 ELECTRONIC GOLD TESTER detects karat value, 9K-18K, but it will indicate “18K or better” if it’s greater than 18K. 

The RS MIZAR ET18 ELECTRONIC GOLD TESTER is billed as the “world’s smallest pocket-size electronic gold tester.”  It will determine if the gold karat value is greater than or equal to 10K, 14K, or 18K.

An advantage of this method over the acid-testing method is that if you are traveling to another state or another country and want to safely buy gold, this type of tester will be a lot more acceptable to the airline!  However, because of the testing solution, you will need to put it in checked-in luggage or ship it ahead to your destination.  Either way, be sure to include all the documentation and keep it with your tester in case there are any questions.

8 Comments on How to Test Gold at Home or When Traveling

Robert


Hi there, I have a Mizar tester. I bought it two years ago; in the beginning it was giving me accurate test, but now I am getting false reading; do you know anything about it? thank you.

What is Fool's Gold? | Gemologist Sam


[...] way to be sure you have real gold instead of fool’s gold is to test it.  Read my post on How to Test Gold at Home or When Traveling to find out [...]

Adam Honeyman


I found this old rusty knife at an auction about 2 years ago and I got it out last week and started to wor on sharping it and i reilized that on top of the handle there was a little sold colored stipe on it and I got online and saw a test that says to put some type of face mascara on the back of your hand and rub the the thing you want to test on the make up and if it’s gold it will leave a black mark. So i was wonderig if this was a reliable test or not.

Frank Coleman


how can you tell if the carat stamp on gold is authentic

vickie price


To Adam
The makeup you are talking about is older cheap lipstick. Red I guess but not sure if other colors are the same.
Key is there is LEAD in some lipsticks, when rubbed on gold it turns either the gold black, or the lipstick where it touched the gold black, I am fuzzy about which. But I am 99% sure it is lipstick you are looking to do rubbing with. It comes off easy enough when done.

Vickie

vickie price


To Robert
I recently bought a brand new Mizar gold tester from Kellyco. It was telling me that stainless steel was 10K, Titanium was 10K. And worse, it told me that 14K white gold was 10K. And it was clearly marked in the ring. Soooo. I sent it back to Kellyco to get a replacement because for some reason it is malfunctioning. And I would say so is yours.
If you have cleaned the electrode inside the cup really well, and stuck to the one drop 3 drop system, then it is not working right anymore and should be sent back to manf. for either a replacement, or a fix.

Vickie

Robert


Im in California and have come into possesion of raw diamonds. I would like to find someone that cuts diamonds or purchases raw diamonds. Im in the central valley and close to Fresno…..any help or methods of finding crafters that does this kind of work?
Thanks

Steve sant


Hi,here in the uk ‘legal’ gold is 9k. I recently tested an item using the magnetic test and a scratch test on glass.the item appeared to be gold but when I took it to a jeweller he did an ‘acid’ test and found the scratch mark made turned not green or grey but a bronze colour which he confessed he had not seen before.The item is not hallmarked but marked simply with the figure ’9′ and I think is of Dutch or Belgian origin. What would the bronze clouring indicate? have you any idea? Thanks.

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