How to Tell If Gold Is Real: 8 Tests from Hallmarks to Specific Gravity

To tell if gold is real, start with the stamp (585 or 14K), then use a magnet to rule out obvious fakes, then measure density with a scale and a glass of water: 14K yellow gold comes out near 13.1, 18K near 15.6. No single home test is conclusive; a jeweler’s acid or XRF test settles it.

Every home test for gold answers a narrower question than people think. A hallmark tells you what someone stamped. A magnet tells you what the piece is not. Density tells you whether the whole piece, not just its surface, has the weight gold should have. Used together, in this order, they catch almost every fake you are likely to meet, without damaging anything.

The 8 tests at a glance

1. Read the hallmark

Look inside a ring, on a clasp or on an earring post. Karat gold is stamped either in karats or as parts per thousand: 10K or 417, 14K or 585, 18K or 750, 24K or 999. In the United States, a stamp must match the metal within tight tolerances under the National Stamping Act. The limitation is obvious: anyone can stamp anything. Treat a stamp as the claim you are about to test, not the answer.

2. Try a magnet

Gold is not magnetic. Hold a strong magnet, ideally a neodymium one, against the piece. If it jumps to the magnet, it contains iron, nickel or steel under whatever is on the surface. If it doesn’t, you have only ruled out the crudest fakes: plated brass, copper and many other base metals are not magnetic either. A clasp spring may be steel even on a real gold chain, so test the body of the piece, not the clasp.

3. Measure density with water

This is the most useful test you can do at home, because it measures the whole piece rather than its surface. Gold is far denser than the metals used to fake it, so a gold-plated piece of brass weighs much less than solid gold of the same size.

You need a kitchen scale that reads to 0.01 g and a small cup of water.

• Weigh the piece dry and note the weight in grams.
• Place the cup of water on the scale and zero it.
• Hang the piece on a thread so it is fully under water without touching the sides or bottom, and read the scale. That reading, in grams, is the volume of water displaced in cubic centimeters.
• Divide the dry weight by that reading. The result is the specific gravity.

Compare your result with the table.

A piece stamped 14K that measures 8 or 9 is not solid 14K gold. Exact figures vary a little with each alloy, and small pieces are hard to measure precisely on a kitchen scale, so look for a result in the right neighborhood rather than an exact match. Stones, hollow links and anything that traps air will throw the reading off, so the test works best on solid, unset pieces.

Specific gravity figures are from Stuller’s reference table.

4. Judge the weight for its size

Even without water, a solid gold piece feels heavy for its size. A chain that feels light and puffy may be hollow, which is still real gold, just less of it. Our guide to hollow vs solid gold explains how to tell.

5. Watch for discoloration

Plated pieces wear through at the edges first: look for a different color showing on the high points, the clasp and the inside of a ring. Base metal under the plating can also leave a green mark on skin. This is weak evidence on its own, because some genuine low-karat gold alloys can mark skin too. Our article on why jewelry marks skin explains why.

6. The ceramic streak test

Drag the piece across the back of an unglazed ceramic tile. Real gold leaves a gold-colored streak; many fakes leave a grey or black one. It works on cheap fakes, but it scratches the piece, and a thick layer of plating can pass. We would not do it to anything you care about.

7. The acid test

Jewelers file a tiny mark on an inconspicuous spot and apply testing acids of known strength. Base metal and plating react; gold of the right karat does not. In skilled hands it is accurate, but it involves nitric acid and leaves a small mark, so leave it to a jeweler.

8. XRF analysis

An X-ray fluorescence analyzer reads the exact composition of the metal in seconds without touching it. It is the most reliable test available and is what dealers and assay offices use. Many jewelers and gold buyers will test a piece for a small fee.

The reliability notes for the magnet, ceramic, acid and XRF tests follow BullionByPost’s guide to testing gold.

What the tests cannot tell you

A density test and a stamp confirm purity. They do not confirm construction. A hollow 14K chain is real 14K gold and will pass every test above, while containing far less gold than a solid one of the same width. When you buy, ask for the construction and the weight in grams as well as the karat. Our listings state the metal and karat, and our Gold Integrity page explains how we describe construction.

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