How Do You Identify Precious Metals?

To identify precious metals, check the purity stamp, weight and dimensions, then confirm with an assay certificate from an accredited laboratory. Simple checks can rule out some fakes, but they cannot prove purity on their own.

Look for purity marks and hallmarks

Purity stamps show the fineness of the metal. Gold is often marked 999 or 9999 for high purity, 916 for 22 carat and 585 for 14 carat. Silver is commonly marked 999 or 925 for sterling. Platinum is often marked 950 or 999. A stamp is a claim by the maker, so it should be backed by documentation.

Check weight and dimensions

Weigh the item on a calibrated scale and measure its size. Compare the figures with the maker’s specification. A bar that is too light or the wrong size for its stated weight is a warning sign.

Use a magnet and a density check

Gold, silver and platinum are not magnetic in their pure form, so a strong magnet that sticks to an item is a warning sign. A density test, which compares weight in air with weight in water, can reveal hollow or filled items, but it is not conclusive on its own.

Be cautious of tungsten-core bars

Tungsten has a density close to gold, so some counterfeit bars are gold-plated tungsten. Standard weight and size checks may not catch them. Ask for an assay, use non-destructive testing such as X-ray fluorescence where available, and buy from reputable dealers with traceable sourcing.

Get an assay certificate

An assay from an accredited laboratory gives the most reliable result. Ask for the testing method, the date and the laboratory’s accreditation. Our article on what counts as a precious metal explains the background.

What a Good Assay Report Includes

A reliable assay report names the laboratory and its accreditation, describes the item tested, and states the method used. It gives the measured purity and the uncertainty of the measurement, along with the date of testing and a unique reference number so the report can be matched to the item.

If a report omits the method or the uncertainty, ask the issuer to explain. Keep the original report with the item, and check that the item is still the one described.

Key Points

• Check purity stamps, weight and dimensions first.
• Gold, silver and platinum are not magnetic in their pure form.
• Tungsten-core fake bars can pass simple weight checks.
• An accredited assay certificate gives the most reliable result.

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