Testing Gold: Electronic, Acid or Touchstone?

Any time you’re serious about buying gold, even if it’s from a trusted friend or family member, it’s important to determine three things. First, is it real gold? Second, is it pure gold or gold-plated? Third, what Karat gold is it? Testing is important because it determines the value of the piece. People may misremember where they got the item, or it may have been a gift the recipient assumed was real gold but isn’t. There’s also a possibility the person doesn’t think it’s as high quality as it actually is. To be fair to both yourself and the seller, always test every gold piece before buying. Here are your options.

Electronic Gold Testing

Electronic Gold Test

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Testing gold electronically is the newest method for determining purity. You’ll need an electronic circuit, testing plate and a bottle of testing acid, which are available in all-inclusive kits. Put a small scratch in the item before testing. The reason for scratching is to determine if the piece is solid gold, not just gold-plated.

Put an entire bottle of testing acid on the plate. Dip the gold item into the solution without touching the test plate. The advantage of the electronic method is you only need a single bottle of acid to test for Karats 9k to 24k. The disadvantage is you have to use a new bottle for every item you test.

Acid Gold Testing

Gold Acid Test

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Acid testing is the most common method, but its name is misleading because all methods require acid. You’ll need a bottle of test acid for each Karat (9k, 10k, 12k, 14k, 18k, 22k and 24k), a color matching chart (which usually comes with your acid) and something to scratch the gold item with, such as a pocket knife or file.

Scratch the gold (to make sure you’re testing underneath any possible plating) and begin with the lowest Karat acid. Apply the acid and compare the color it turns to the colors on your chart until you spot a match. Normally, real gold stains brown and imitation pieces turn green or bubble. After testing, wash the acid off with water and use a pencil eraser to buff off the stain.

Touchstone Gold Testing

Touchstone Gold Test

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Touchstones are usually made of finely textured glass, fieldstone or slate. You’ll need gold testing acid and actual gold sample pieces of each Karat, to compare the test item to.

Rub the test item across the touchstone and do the same with one of the sample pieces to make side by side marks. Apply testing acid to each mark until you get a match. Touchstone testing is best reserved for cases where you’re already sure the item is gold, but aren’t sure of the exact Karat.

A Word About Magnet Testing

Magnet Gold Testing

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Many websites and amateur testers recommend testing gold pieces with a magnet before you buy. However, this is a bad business practice if you’re serious about investing in gold. Magnets are drawn to fake gold and not to real gold, so it’s fine to use a magnet before performing a touchstone test. But never depend on a magnet test alone to price gold. Because you can’t be sure of its purity, there’s no way to offer a fair price. Test Karats using electronic, acid or touchstone methods.

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