How to Identify Real Gold? 5 Reliable Tests You Can Do at Home

A gold jewel tarnished by time, offered as a gift. An online purchase at an attractive price. An inherited ring whose hallmark you cannot identify. Gold is everywhere, and so are imitations. Verifying the authenticity of a piece of jewellery helps you avoid unpleasant surprises and understand the true value of what you own.

We present 5 simple, reliable tests to identify gold at home, without any laboratory equipment. Some are accessible to everyone; others require a few basic materials. All are based on the physical and chemical properties of gold.

The hallmark is the official signature of a piece's gold content. It is the first thing to look for on any jewel. In France, hallmarks are mandatory on all solid gold jewellery weighing more than 3 grams.

French hallmarks indicate the gold content in parts per thousand. Look for them on the inside of a ring, on the clasp of a necklace or bracelet, or on the back of an Earring. You should see an engraved number, sometimes accompanied by a symbol:

• 750 (or an eagle's head) = 18K gold (75% pure gold)
• 585 (or a scallop shell) = 14K gold (58.5% pure gold)
• 375 (or a clover) = 9K gold (37.5% pure gold)

Source: Table of guarantee hallmarks applied in France, French Customs and the Monnaie de Paris

The 750 hallmark is the standard of French fine jewellery. It is the gold content we use at Mayuri for all our solid gold creations, as it offers the finest balance between purity and everyday durability.

French vermeil bears a specific hallmark in the shape of a V (sometimes accompanied by a Minerva head). Please note: French vermeil requires a gold layer of 5 microns minimum on a solid 925 silver base. This is a strict standard, far more demanding than American vermeil (often just 2.5 microns).

Gold-plated jewellery, on the other hand, generally does not carry an official hallmark. The gold layer is extremely thin (0.5 to 3 microns) and wears away over time. Plated pieces are marked "plaqué or," "gold plated," or "GP." If you see no hallmark and the price is very low, it is most likely plated or an imitation.

If you would like to explore the French hallmarking system in greater depth and learn to read the various symbols, we have written a comprehensive guide detailing each hallmark.

Pure gold is not magnetic. This is one of its fundamental properties, rooted in its atomic structure. If your piece of jewellery clings to a powerful magnet (a neodymium magnet, found in speakers or toys), it does not contain solid gold.

Obtain a neodymium magnet (available at hardware stores for just a few dollars). Hold it close to the piece. If the jewellery is attracted to it, it contains a ferrous metal beneath a gold plating, or it is not gold at all. If there is no reaction, that is a good sign.

A word of caution: some gold alloys contain small amounts of non-magnetic metals (silver, copper, palladium). White gold may sometimes contain nickel in older formulations or those produced outside the EU, and nickel is slightly magnetic. This test therefore cannot distinguish 18K gold from vermeil or gold-plated jewellery, as all three may pass the magnet test.

In summary: the magnet test rules out obvious fakes, but it is not sufficient to certify a piece. Use it in combination with other tests.

Rub the piece against an unglazed ceramic surface (the underside of a plate, a bathroom tile, or a gemological touchstone). Authentic gold leaves a golden yellow streak, faint but visible. A plated or base metal piece leaves a black or grey streak.

This test works because gold is softer than ceramic: it wears very slightly when rubbed and deposits a fine powder. Base metals (copper, brass, iron) oxidise on contact with air and leave dark marks.

Rub gently, without pressing too hard, especially on a piece you care about. The test leaves a micro-scratch invisible to the naked eye on 18K gold, but it may be more noticeable on a plated piece, potentially revealing the underlying metal.

If the streak is yellow and the piece does not cling to a magnet, you most likely have gold. If the streak is black, it is a plated piece or an imitation.

Authentic gold is chemically inert: it does not react to white vinegar (a mild acetic acid). Base metals such as copper and brass oxidise on contact with acid and change colour.

Apply a few drops of household white vinegar to the piece. Leave it on for 10 to 15 minutes. Rinse with clean water and dry thoroughly. If the piece retains its original colour, it is likely gold. If a green or black stain appears, the piece is plated or made from an alloy with a low gold content.

This test is safe for solid gold, vermeil, and even silver (the base of vermeil). It is quick, free, and accessible to everyone. One word of caution: white gold may contain palladium or nickel, both of which react very little to vinegar. A false negative is therefore possible, meaning the piece does not react, yet it is not gold.

Gold has an exceptionally high density: 19.3 g/cm³, making it one of the heaviest metals in existence. A solid gold piece sinks immediately in water. A plated or lightweight imitation, such as hollow copper or aluminium, sinks more slowly or may even float.

Fill a glass with water and gently place the piece on the surface. If it sinks at once, this is consistent with gold. If it floats or descends slowly, treat the result with caution.

This test is approximate. It cannot distinguish between 18K gold (density 15 to 16 g/cm³ depending on the alloy), lead (density 11.3), or tungsten (density 19.3, used in certain counterfeits). For a precise measurement, you would need to weigh the piece dry, weigh it submerged, and calculate its volume using Archimedes' principle. This is achievable, but it does require a precision scale.

At-home tests are useful for an initial assessment. They help rule out obvious fakes and give you a sense of the purity. However, they are no substitute for professional expertise in three specific situations:

• You are purchasing a significant gemstone (Ruby, Sapphire, or Emerald over 1 carat or priced above $4,800; or a Diamond over 0.8 carat). A certificate from a gemological laboratory such as GIA, HRD, or SSEF guarantees the authenticity of both the stone and its setting.
• The piece holds sentimental or historical value (a family heirloom or an antique piece). A specialist will determine whether it is solid gold, vermeil, or simply plated. They will also identify the hallmark and the period of manufacture.
• You still have doubts after running your tests. The vinegar produces no reaction, yet the hallmark is illegible or absent. The density appears correct, but the colour seems off. A gemologist or jeweller can provide a definitive answer in five minutes, using a touchstone and nitric acid.

We always recommend consulting a professional before purchasing a second-hand piece online, especially when the price seems unusually low for the stated purity.

Many people confuse these three categories, yet the differences are significant, both in terms of durability and price.

18K gold is the standard of fine jewellery. It retains its brilliance for decades, even across generations. French vermeil is a lasting alternative for those seeking the aesthetic of gold at a more accessible price point, provided it meets French standards (a minimum of 5 microns). Gold plating, on the other hand, is a temporary solution: it wears away, darkens, and gradually reveals the base metal beneath.

If you would like to care for your gold jewellery on a daily basis and preserve its brilliance over time, we have brought together all our methods in a comprehensive guide.