How to Test if Gold is Real: The Methods That Actually Work When You Need to Know

I've been around gold long enough to see people get burned – literally and figuratively. Last month, a friend brought me what she thought was her grandmother's gold necklace, only to discover after some simple tests that it was brass with a thin gold coating. The disappointment on her face reminded me why knowing these testing methods matters beyond just satisfying curiosity.

Gold has this peculiar way of making people both excited and paranoid. You inherit a piece, find something at an estate sale, or receive a gift, and suddenly you're wondering: is this the real deal? The good news is that you don't need to be a metallurgist or own expensive equipment to get a pretty solid answer.

The Weight of Truth

Real gold is heavy. Ridiculously heavy, actually. When I first held a genuine gold coin versus a gold-plated one of the same size, the difference shocked me. Gold has a density of 19.3 grams per cubic centimeter – that's nearly twice as dense as lead. Pick up a piece of suspected gold jewelry and really feel its weight. Does it feel substantial for its size? Or does it feel like costume jewelry?

This density test becomes more precise if you have a scale and can do some basic math. Weigh your item, then submerge it in water and measure the volume of water it displaces. Divide the weight by the volume, and you'll get the density. If it's nowhere near 19.3 g/cm³, you're not holding gold. But here's the thing – this works best for solid pieces. Hollow jewelry throws the whole calculation off.

Magnets Don't Lie (Usually)

Here's something that surprises people: gold isn't magnetic. Not even a little bit. I keep a strong neodymium magnet in my desk drawer specifically for quick gold checks. Hold it near your piece – if there's any pull at all, you've got iron or nickel in there, which means it's not pure gold.

But wait, there's a catch. Some fake gold is made from non-magnetic metals like copper or aluminum. So while a magnetic pull definitely means "not gold," no magnetic pull doesn't guarantee you've struck gold. It's like a one-way street of truth.

The Ceramic Plate Method

This one feels almost too simple to work, but it does. Find an unglazed ceramic plate – the back of a bathroom tile works perfectly. Drag your gold item across it with moderate pressure. Real gold leaves a golden streak. Fake gold typically leaves a black mark.

I discovered this method by accident years ago when my wedding ring scraped against a flower pot. The golden line it left made me curious enough to test every piece of "gold" jewelry I owned. Let's just say I had some disappointing revelations that day.

Nitric Acid: The Nuclear Option

When you absolutely need to know, nitric acid provides the answer. This test has been used by jewelers and pawn shops for decades because it's definitive. A drop of nitric acid on fake gold will turn green. On real gold? Nothing happens. The metal just sits there, unimpressed by the acid's attempts to corrode it.

You can buy gold testing kits that include different strengths of acid for testing different karats. The 10K acid won't affect 14K gold, the 14K acid won't affect 18K gold, and so on. It's like a ladder of chemical truth.

But here's my warning: this test leaves a mark. Don't do it on the visible part of grandma's brooch. Test on an inconspicuous spot, like the inside of a ring band or the back of a pendant.

The Skin Test (With Caveats)

You've probably heard that fake gold turns your skin green. This is... sort of true. Copper in fake gold jewelry oxidizes and can leave green marks on your skin, especially when mixed with sweat or lotions. But high-quality gold plating might not cause any discoloration for months or even years.

More interesting is the foundation test. Rub liquid foundation on your hand, let it dry, then rub the gold across it. Real gold often leaves a black line on the makeup, while fake gold doesn't. Why? Nobody's entirely sure, but it has something to do with the way gold particles interact with the zinc and titanium oxides in foundation. Science is weird sometimes.

Professional Electronic Testing

If you're serious about gold testing – maybe you're getting into buying gold coins or estate jewelry – consider investing in an electronic gold tester. These devices use electrical conductivity to determine gold content. They're not cheap (expect to pay $200-$500 for a decent one), but they're non-destructive and surprisingly accurate.

I bought one after getting burned on what I thought was a great deal on some "gold" coins at a flea market. The tester paid for itself the first time it saved me from another bad purchase. These devices can even tell you the karat rating, which is pretty impressive for something the size of a large pen.

The Float Test Myth

Let me bust a persistent myth: the float test. People claim that real gold sinks while fake gold floats. This is nonsense. Whether something floats depends on its density relative to water and its shape. A thin piece of gold leaf will float due to surface tension, while a lead fishing weight painted gold will sink like a stone. Skip this "test" entirely.

Understanding Hallmarks and Stamps

Before you start scratching ceramic plates or dropping acid, check for hallmarks. Real gold jewelry usually has stamps like "14K," "585" (meaning 58.5% gold, which equals 14K), "18K," "750," and so on. But – and this is crucial – stamps can be faked. I've seen plenty of "14K" stamps on brass jewelry.

What's harder to fake is the quality and precision of genuine hallmarks. Real stamps are usually crisp, evenly pressed, and professionally done. Fake stamps often look wonky, uneven, or poorly aligned. It's like comparing a genuine signature to a forgery – once you know what to look for, the differences become obvious.

The Vinegar Test

Here's a gentle test that won't damage your piece: white vinegar. Put your gold item in a small container and cover it with white vinegar. Let it sit for about 15 minutes. Real gold won't change color or corrode. Fake gold might change color, develop spots, or show signs of wear.

This test works because gold is incredibly non-reactive. It's why gold artifacts from ancient Egypt still look pristine after thousands of years in tombs. The metal simply doesn't care about most chemicals.

When Multiple Tests Matter

No single test is foolproof. That's why professionals use multiple methods. A piece might pass the magnet test but fail the acid test. It might have the right weight but leave black marks on ceramic. Think of each test as gathering evidence for your case.

I learned this lesson when testing a "gold" watch I inherited. It passed the magnet test, had the right hallmarks, and felt heavy. But the acid test revealed it was gold-filled – a thick layer of gold bonded to base metal. Not worthless, but not solid gold either.

The Professional Appraisal

Sometimes, you need to call in the experts. A professional jeweler or certified appraiser has tools and experience you don't. They can use X-ray fluorescence machines that analyze metal composition without any damage. They know the subtle signs of different gold alloys and plating techniques.

Yes, appraisals cost money – usually $50-$150 per piece. But if you're dealing with potentially valuable items or making important financial decisions, it's worth it. I've seen people discover their "costume jewelry" was actually worth thousands, and I've seen others learn their "investment" was worth its weight in brass.

Final Thoughts on Gold Testing

Testing gold is part science, part art, and part detective work. Each method tells you something different, and together they paint a picture of what you're really holding. The ceramic test is great for quick checks, the acid test for definitive answers, and electronic testers for regular use.

But here's what I've learned after years of handling gold: sometimes the story behind a piece matters more than its metal content. That gold-plated locket from your grandmother might not be worth much to a gold buyer, but its sentimental value is priceless. Test your gold to satisfy curiosity or make informed decisions, but don't let the results diminish the personal meaning of inherited pieces.

The real value in knowing these tests isn't just about avoiding fakes – it's about approaching gold purchases and inheritances with confidence. Whether you're at an estate sale, pawn shop, or cleaning out a relative's jewelry box, you now have the tools to separate the real from the merely shiny.

Remember, gold has captivated humans for millennia not just because of its monetary value, but because of its unique properties – its permanence, its beauty, its resistance to tarnish and time. When you test a piece and discover it's real gold, you're holding something that will outlast civilizations. That's pretty remarkable, when you think about it.

Authoritative Sources:

Revere, Alan. Professional Jewelry Making. New York: Van Nostrand Reinhold, 1991.

McCreight, Tim. The Complete Metalsmith: An Illustrated Handbook. Worcester: Davis Publications, 1991.

United States Geological Survey. "Gold Statistics and Information." USGS.gov. U.S. Department of the Interior, 2023.

Untracht, Oppi. Jewelry Concepts and Technology. New York: Doubleday, 1985.

Young, Robert S. The Analytical Chemistry of Gold. Oxford: Pergamon Press, 1980.