How to Tell if Gold Is Real — 7 At-Home Tests

Whether you have inherited a piece, bought from an uncertain source, or simply want to verify what you own, knowing how to test gold authenticity is valuable knowledge. Real gold has specific physical properties that fakes cannot replicate. Several of these properties can be tested at home with common items, while others require professional equipment. Understanding which tests are reliable, and which can damage your jewellery, prevents both deception and accidental harm to genuine pieces.

This guide covers seven at-home gold tests ranging from completely safe (hallmark inspection, magnet test) to more involved (density test) to those best left to professionals. Each test reveals different information. Combining several tests provides reliable authentication for most purposes.

KEY TAKEAWAYS

✦ Hallmark stamps are the first and easiest indicator, but can be faked

✦ Real gold is not magnetic, the magnet test quickly identifies many fakes

✦ The float test works because gold is dense and sinks immediately

✦ Skin discolouration indicates the piece is not solid gold

✦ For valuable pieces, professional testing is the only definitive method

Test 1: The Hallmark Inspection

The first and easiest check. Genuine gold jewellery is typically stamped with a hallmark indicating purity.

What to look for: Karat marks (24K, 22K, 18K, 14K, 10K, 9K) or numerical purity marks (999, 916, 750, 585, 375). These usually appear on the inside of rings, on the clasp of necklaces and bracelets, or on the post of earrings.

What it means: A hallmark indicates the manufacturer claims specific gold purity. In the UK, hallmarks are legally regulated by assay offices and provide strong authenticity indication.

The limitation: Hallmarks can be faked on counterfeit pieces. A hallmark alone does not guarantee authenticity, but its absence is a warning sign. Also note markings like GP (gold plated), GF (gold filled), GEP (gold electroplate), or HGE (heavy gold electroplate) which indicate the piece is NOT solid gold.

Use a magnifying glass to read small hallmarks clearly. Jewellers' loupes (10x magnification) are inexpensive and reveal marks invisible to the naked eye.

Test 2: The Magnet Test

Gold is not magnetic. This simple test quickly identifies many fakes.

What you need: A strong magnet (rare earth or neodymium magnet works best, fridge magnets are too weak).

Steps:

1. Hold the magnet near the gold piece.

2. Real gold shows no attraction to the magnet.

3. If the piece is pulled toward the magnet, it contains magnetic metals (iron, nickel, steel) and is not solid gold.

The limitation: Some gold fakes use non-magnetic base metals (brass, copper) that also do not respond to magnets. Passing the magnet test does not confirm authenticity, but failing it confirms the piece is not solid gold. Note that many quality gold plated pieces use surgical steel base, which IS slightly magnetic, this is normal for quality plated jewellery, not a sign of fake solid gold.

Test 3: The Skin Test

Real gold does not react with skin. Discolouration indicates base metals.

What to observe: Wear the piece for several days. Real solid gold leaves no marks on skin. If your skin turns green, black, or shows any discolouration where the piece contacts it, the piece contains base metals (copper, brass) and is not solid gold.

What it means: Solid 14K, 18K, and higher gold does not cause skin discolouration. Green or black marks indicate copper content, present in cheap plated or brass pieces but not in solid gold.

The limitation: This confirms whether a piece is solid gold but takes days and does not distinguish between quality gold plated (which may not discolour if on surgical steel base) and solid gold.

For complete information on skin discolouration, see Why Does My Jewellery Turn My Skin Green.

Test 4: The Float Test

Gold is extremely dense. Real gold sinks immediately in water.

What you need: A glass of water deep enough to submerge the piece.

Steps:

1. Drop the gold piece gently into the water.

2. Real gold sinks immediately to the bottom due to its high density (gold is one of the densest metals).

3. If the piece floats or sinks slowly, it is not solid gold. Fakes made from lighter metals do not sink with the same immediacy.

The limitation: Dense fake metals (tungsten, lead) also sink, so passing does not confirm authenticity. But floating or slow sinking confirms the piece is not solid gold. This test is completely safe for the jewellery.

Test 5: The Ceramic Scratch Test

Gold leaves a distinctive mark on unglazed ceramic. Use with caution as it can scratch the piece slightly.

What you need: An unglazed ceramic tile or the unglazed bottom of a ceramic plate.

Steps:

1. Gently drag the gold piece across the unglazed ceramic surface.

2. Real gold leaves a gold-coloured streak.

3. Fake gold (or gold plated) leaves a black streak.

The limitation: This test can leave a small mark on the jewellery. Use only on an inconspicuous area, or avoid entirely for valuable or sentimental pieces. Not recommended for pieces you care about.

Test 6: The Density Test

The most accurate at-home test, calculating the piece's density to compare against gold's known density.

What you need: Accurate digital scale (0.1g precision), measuring container with millilitre markings, water, calculator.

Steps:

1. Weigh the dry gold piece in grams. Record the weight.

2. Fill the measuring container with water and note the exact volume in millilitres.

3. Submerge the piece fully and note the new water level.

4. The difference in water level is the piece's volume in millilitres (cubic centimetres).

5. Divide the weight by the volume to get density (g per cm³).

6. Compare: pure gold has density around 19.3 g/cm³. 18K gold around 15.5. 14K gold around 13.0. Significantly lower density indicates base metals or hollow construction.

The limitation: Requires accurate tools and careful measurement. Small measurement errors produce misleading results. Best for larger solid pieces where measurement precision is achievable.

Test 7: Professional Testing

For valuable pieces or definitive answers, professional testing is the only reliable method.

PROFESSIONAL GOLD TESTING METHODS

Method	How It Works	Cost
Acid test	Nitric acid reaction	€5-15
Electronic tester	Electrical conductivity	Free-€10
XRF spectrometer	X-ray composition analysis	€15-40
Assay office	Official certified analysis	€30-80

When to use professional testing: Inherited pieces of unknown value, purchases from uncertain sources, pieces you intend to sell, insurance appraisals, and any situation where definitive authentication matters. Many jewellers offer free or low-cost electronic testing.

DID YOU KNOW

Gold's density is so distinctive that it has been used to detect fakes for over 2,000 years. The famous 'Eureka' moment attributed to Archimedes around 250 BCE involved using water displacement to determine whether a crown was pure gold or had been adulterated with silver. Archimedes reportedly realised that a given weight of gold displaces less water than the same weight of less-dense silver, allowing him to detect fraud without damaging the crown. This same density principle underlies the modern float test and density test. Gold's density of 19.3 g/cm³ is nearly twice that of most base metals, making density one of the most reliable indicators of authenticity.

THE BOTTOM LINE

Real gold has specific physical properties that fakes cannot fully replicate. Start with the hallmark inspection (karat marks like 18K, 14K, or numerical marks like 750, 585), then use the magnet test (real gold is not magnetic), the skin test (real gold does not discolour skin), and the float test (real gold sinks immediately due to high density). The density test is the most accurate at-home method but requires precise tools. The ceramic scratch test works but can mark the piece. No single at-home test is definitive, combining several provides reliable authentication for most purposes. For valuable pieces, inherited items of unknown worth, or definitive answers, professional testing (acid test, electronic tester, XRF, or assay office) is the only reliable method, often available free or cheaply at jewellers.

For understanding gold quality categories, see [Link: Gold Filled vs Gold Plated vs Solid Gold — The Complete Comparison].

Frequently Asked Questions

Q: How can I tell if gold is real at home?

A: Start with the hallmark inspection, looking for karat marks (18K, 14K) or numerical purity marks (750, 585) usually stamped inside rings or on clasps. Then use the magnet test (real gold is not magnetic, so attraction to a strong magnet indicates fake). The float test confirms density (real gold sinks immediately in water). The skin test over several days reveals base metals (real gold does not discolour skin). No single test is definitive, so combine several. For valuable pieces, professional testing at a jeweller (often free electronic testing) provides definitive answers.

Q: Does real gold stick to a magnet?

A: No, real gold is not magnetic and shows no attraction to magnets. If a piece is pulled toward a strong magnet, it contains magnetic metals (iron, nickel, steel) and is not solid gold. However, the reverse is not fully conclusive: some fakes use non-magnetic base metals (brass, copper) that also do not respond to magnets, so passing the magnet test does not confirm authenticity. Note that quality gold plated pieces on surgical steel base ARE slightly magnetic, which is normal for plated jewellery, not a sign of counterfeit solid gold.

Q: What does a hallmark on gold mean?

A: A hallmark indicates the claimed gold purity, shown as karat marks (24K, 22K, 18K, 14K, 10K, 9K) or numerical purity (999, 916, 750, 585, 375). In the UK, hallmarks are legally regulated by assay offices and provide strong authenticity indication. Marks appear inside rings, on clasps, or on earring posts. Watch for markings that indicate the piece is NOT solid gold: GP (gold plated), GF (gold filled), GEP (gold electroplate), HGE (heavy gold electroplate). While hallmarks can be faked on counterfeits, their absence is a warning sign warranting further testing.

Q: Does real gold turn skin green?

A: No, real solid gold (14K, 18K, and higher) does not turn skin green or cause any discolouration. Green or black marks where jewellery contacts skin indicate copper content, present in cheap plated pieces or brass jewellery but not in solid gold. If your gold piece discolours your skin, it is not solid gold. Note that quality gold plated on surgical steel base may also not discolour skin, so the skin test confirms a piece is not solid gold if it DOES discolour, but passing does not distinguish quality plated from solid gold.

Q: Will the ceramic scratch test damage my gold?

A: The ceramic scratch test can leave a small mark on the jewellery because it involves dragging the piece across an abrasive unglazed ceramic surface. Real gold leaves a gold-coloured streak while fakes leave black streaks. However, because of the marking risk, only use this test on an inconspicuous area of the piece, or avoid it entirely for valuable or sentimental jewellery. Safer alternatives that do not risk damage include the hallmark inspection, magnet test, float test, and skin test. For valuable pieces, professional non-destructive testing is preferable.

Q: Is professional gold testing worth it?

A: For valuable pieces, inherited items of unknown worth, purchases from uncertain sources, pieces you intend to sell, and insurance appraisals, professional testing is worth it because it provides definitive answers that at-home tests cannot. Many jewellers offer free or low-cost electronic conductivity testing. Acid testing costs €5 to €15, XRF spectrometer analysis €15 to €40, and official assay office certification €30 to €80. For inexpensive pieces or simple curiosity, at-home tests (hallmark, magnet, float, skin) provide reasonable indication without cost. Match the testing investment to the piece's value and the importance of certainty.

Q: How accurate is the density test for gold?

A: The density test is the most accurate at-home method when done carefully. It calculates the piece's density (weight divided by volume) to compare against gold's known density: pure gold around 19.3 g/cm³, 18K around 15.5, 14K around 13.0. Significantly lower density indicates base metals or hollow construction. However, accuracy depends on precise measurement, requiring an accurate digital scale (0.1g precision) and careful volume measurement via water displacement. Small measurement errors produce misleading results. The test works best on larger solid pieces where measurement precision is achievable. Dense fake metals like tungsten can produce similar density, so it is not fully definitive.