Authenticity Testing

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

The coin dimensions check measures the diameter and thickness of a coin with callipers or a gauge and compares the values against the official minting specifications, exposing forgeries through deviating measurements.

The coin weight check is a simple, non-destructive method of authenticity control for precious-metal coins, in which the actual weight is compared with the manufacturer's official target weight.

A non-destructive method for the authenticity testing of precious metals by measuring the specific density according to the Archimedean principle.

A magnifier, typically with 10x to 30x magnification, used to inspect fineness stamps, hallmarks and striking features on precious-metal coins and bars.

The ice melt test uses the exceptionally high thermal conductivity of silver to distinguish genuine silver from fakes: an ice cube melts noticeably faster on a genuine silver coin or silver 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 not magnetic and are not attracted.

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

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

Sigma Metalytics is a range of handheld instruments that gauge the resistivity of precious metals through electromagnetic induction, dependably flagging fakes.

The streak test is a classic chemical procedure 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 counterfeit is a fake gold or platinum bar or coin in which a tungsten core is coated with a thin layer of precious metal, exploiting the almost identical density of tungsten (19.25 g/cm³) and gold (19.32 g/cm³).

A non-destructive testing method that uses sound waves in the ultrasonic range 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.