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.
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.