How to Check if a Gemstone is Real or Fake at Home

So you just bought a beautiful gemstone — or maybe found one in an old jewellery box. It looks stunning. But is it real? With so many imitation stones, synthetic copies, and glass fakes in the market, knowing how to test a gemstone at home is a skill every buyer needs. The good news? You don't need a laboratory. With a few simple tests, you can get a clear idea whether your gemstone is genuine or not.

Why Fake Gemstones Are So Common

The gemstone market is enormous — and unfortunately, so is the number of fakes. Sellers may pass off glass, plastic, synthetic stones, or low-quality materials as genuine gems, especially online. Whether you're buying a ruby, emerald, turquoise, or Cat's Eye stone, the risk of getting a fake is very real.

That's why knowing the basics before spending your money is so important. Here are seven tests you can do right at home.

The Visual Inspection Test

Start with your eyes. Real gemstones form naturally over thousands of years, and that process leaves traces.

What to look for

Natural inclusions: Real stones often have tiny internal flaws — bubbles, cracks, or cloud-like structures. A perfectly flawless stone at a low price is often synthetic or glass.
Colour consistency: Natural gems have slight colour variations. If the colour looks too uniform or vivid throughout, it may be dyed or synthetic.
Round bubbles: If you see perfectly round bubbles under a magnifying glass, it's almost certainly glass. Natural stones don't have round bubbles.

💡 Tip: Use a jeweller's loupe or your phone camera (zoom in under good light) to inspect the stone closely.

The Scratch Test

Gemstones are rated on the Mohs hardness scale (1–10). Harder stones scratch softer materials, but not the other way around.

How to do it

Try scratching the stone with a steel knife (hardness ~5.5). If it scratches easily, it's likely glass or a soft fake.
Real rubies, sapphires, and diamonds are extremely hard (9–10 on the Mohs scale) and won't be scratched by a knife.
Softer genuine stones like turquoise or moonstone (hardness 5–6) can scratch — so don't rely on this test alone for softer gems.

⚠️ Caution: This test can damage the stone surface. Do it only on an inconspicuous spot, or skip it for polished jewellery.

The Temperature Test

Natural gemstones conduct temperature differently from glass or plastic.

How to do it

Hold the stone in your hand or place it on your cheek for a few seconds.
Real gemstones feel cool to the touch and warm up slowly.
Glass also starts cool but warms up almost immediately.
Plastic fakes reach room temperature almost instantly — they feel warm right away.

💡 Note: This test is especially effective for identifying plastic fakes of rose quartz, amethyst, or turquoise.

The Light Refraction Test

Light behaves differently when it passes through a real gemstone versus a fake.

For diamonds

Place the stone face-down on a newspaper. If you can read the text through the stone, it's likely fake. A real diamond refracts light so strongly you won't be able to read through it.

For coloured stones

Shine a torch through the stone at different angles. Real gems show depth, complexity, and shifting colours.
Fakes — especially glass — tend to look flat or show a single uniform colour from all angles.

💡 Bonus: Use a UV light. Some real gemstones (diamonds, rubies, Cat's Eye) fluoresce under UV, while fakes typically don't.

The Weight Test

Real gemstones tend to be denser than glass or plastic imitations of the same size.

How to do it

Hold the stone in your palm and compare it with a similar-sized piece of glass.
If the stone feels surprisingly light for its size, it might be plastic or hollow glass.
Stones like garnet, sapphire, and spinel are noticeably heavier than glass of equal volume.

This is a rough test — not definitive — but combined with others, it adds useful information.

The Water Test

A simple test for stones sold as quartz or crystal varieties.

How to do it

Drop the stone into a glass of water.
Real gemstones (especially quartz varieties like rose quartz, amethyst, or citrine) are very dense and sink quickly.
Fake plastic stones may sink too, but feel lighter when you hold them underwater.

💡 Combine with the temperature test for better accuracy when checking crystal stones.

Check the Setting & Price

Sometimes the biggest clue isn't the stone itself — it's the context.

Unrealistically low price: Genuine rubies, emeralds, and sapphires are expensive. If the price seems too good to be true, it probably is.
Cheap metal setting: Real gemstones are almost never set in cheap alloy or plastic. If the pendant looks low quality, the stone likely is too.
No certification: Reputable sellers provide certificates from labs like GIA, IGI, or government-authorised labs. Always ask for one.

✨ At ClickGems, every gemstone comes with proper certification — so you always know exactly what you're buying. No guesswork, no fakes.

When Home Tests Are Not Enough

Home tests can help you spot obvious fakes, but they have limits. Some synthetic stones (like lab-grown rubies or sapphires) are chemically identical to natural ones — and no home test will catch them. The only way to know for certain is professional gemological testing.

If you're spending a significant amount, always:

Ask for a gemological certificate from a recognised lab.
Buy from a trusted, verified seller with a clear return policy.
Request a refund policy in case the stone doesn't match its description.

Quick Reference: At-Home Gemstone Tests

Test	What It Detects	Reliability
Visual Inspection	Glass bubbles, dye, inclusions	High
Scratch Test	Hardness of stone	Medium
Temperature Test	Plastic vs real / glass	Medium
Light Refraction	Internal complexity	High
Weight Test	Density comparison	Low–Medium
Water Test	Density (for crystals)	Low–Medium
Price & Certification	Authenticity of seller	High

Frequently Asked Questions

Can I test a gemstone at home without any tools?

Yes. The temperature test, visual inspection, and weight test require no tools at all. For better results, a magnifying glass or phone camera helps considerably.

Is a real gemstone always more expensive than a fake?

Generally yes — but price alone isn't proof. Some synthetic gems are sold at high prices. Always look for proper gemological certification from a recognised lab.

What is the most reliable way to tell if a gemstone is real?

Professional gemological testing with proper equipment is the most reliable method. At home, combining 3–4 tests together gives the best overall indication of authenticity.

Do lab-grown gemstones count as fake?

Not exactly. Lab-grown stones are chemically real — they have the same properties as natural gems. They are not "fake," but are usually priced lower as they are not naturally mined. At ClickGems, we clearly label all lab-certified and natural stones so you always know what you're getting.