Authenticity Testing

The acid test is a chemical method for determining the fineness of gold and silver alloys, in which testing acids produce a characteristic colour reaction on the metal surface or on a touchstone.

Coin dimensions verification measures the diameter and thickness of a coin using a caliper or gauge and compares the values with official mint specifications in order to expose forgeries on the basis of deviating measurements.

Coin weight verification is a simple, non-destructive method for checking the authenticity of precious metal coins, in which the actual weight is compared with the official target weight specified by the manufacturer.

Non-destructive method for testing the authenticity of precious metals by measuring specific density using the Archimedean principle.

A loupe with typically 10- to 30-times magnification, used to examine fineness stamps, hallmarks and die details on precious metal coins and bars.

The ice melt test exploits the exceptionally high thermal conductivity of silver to distinguish genuine silver from counterfeits: an ice cube melts visibly faster on a real silver coin or bar than on any other metal.

The magnet test checks whether a precious metal reacts to a strong magnet — genuine gold, silver, and platinum are non-magnetic and are not attracted.

The magnetic scale uses the Lenz effect of precious-metal-specific diamagnetic values to distinguish genuine gold and silver bars or coins from magnetic forgeries.

The ping test is a non-destructive authenticity check in which the characteristic ringing sound of a coin when lightly struck is used to distinguish genuine precious metal coins from counterfeits.

Sigma Metalytics refers to a product line of portable testing devices that measure the specific electrical resistance of precious metals via electromagnetic induction, reliably exposing counterfeits.

The streak test is a classical chemical method for determining the fineness of gold alloys, in which a metal streak on a touchstone is compared with acid solutions of known concentration.

A tungsten forgery is a counterfeit gold or platinum bar or coin in which a tungsten core is coated with a thin layer of precious metal, exploiting the nearly identical density of tungsten (19.25 g/cm³) and gold (19.32 g/cm³).

A non-destructive testing method that uses ultrasonic sound waves to determine the density, internal structure, and material composition of precious metal bars and coins.

A non-destructive analytical method that uses X-ray radiation to precisely determine the elemental composition of precious metals and alloys.