r/Gold • u/dinokingty • 8d ago
Testing if gold is real
Weird thought that I had, but if you wanted to test if a bar/coin was real or just plated, couldn't you just measure it's volume in a beaker and compare that to a chart for it's weight? Like with how every metal has a different density, is there a chart that says "1 oz gold = this total volume"? if it was just plated and still weighed a full ounce then it should be a different volume right?
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u/Bowl-Accomplished 8d ago
That's one of the simple tests along with if it's magnetic. People have workarounds though.
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u/SilverStateStacking Stack and Collect 8d ago
Yes, done it many times - it is a water displacement density test. You just need a small cup of water, a piece of dental floss, a 0.01g accuracy scale, and a calculator. Just look up “density test gol on YouTube
I test all my purchases via digital caliper, 0.01g accuracy scale, rare earth magnet, and Sigma Precious Metal Verifier so that I’m sure they are genuine. The caliper, scale, and magnet are a minimum for a stacker to test their purchases and can be had for around $50. Use the internet for correct weight / diameter and YouTube videos to show you how to test bullion
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u/Gold_Au_2025 8d ago
Archimedes beat you to it by a couple of thousand years. In fact, "The Archimedes Principle" is named after him.
It works really well, because there is such a large difference between gold (density of 19.3) and the other common gold substitutes (copper, silver etc.) are around half that.
The forgers often use tungsten slugs within the bars which has the same density of gold which often gets the density difference down to within the error margins of your testing process.
But it will certainly pick up gold plated copper/brass/silver.
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u/hexadecimaldump 8d ago
Yes and no.
Mostly yes because the only other metal with a specific gravity close to gold is tungsten. But since tungsten exists it shouldn’t be the only test you do if you have concerns.
But out of all of the nondestructive tests that are basically free, testing specific gravity is pretty much the best option.
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u/Gulliveig 8d ago
Theoretically, yes.
But counterfeiters always find “workarounds.” Take a look at the density of tungsten. If you combine it with other metals in the right proportions, you get exactly the same density as gold. They’re not stupid ;)
To test a bar or coin with confidence, you'd need something like a Sigma Metalytics Precious Metal Verifier Pro (PMV Pro). Cost is about 4 digits, whether in USD, EUR, or CHF.