Authenticity Testing

The acid test is a chemical method for gauging 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 a coin's diameter and thickness with a calliper or gauge and compares the readings against the official striking specifications, exposing forgeries by their deviant measurements.

Coin weight verification is a simple, non-destructive way to check the authenticity of a precious-metal coin by comparing its actual weight with the manufacturer's official target weight.

A non-destructive way to check whether a piece of precious metal is genuine by measuring its specific density using Archimedes' principle of buoyancy.

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

The ice melt test exploits the exceptionally high thermal conductivity of silver to tell genuine metal apart from fakes: an ice cube placed on a real silver coin or bar melts noticeably faster than on any other material.

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 exploits the Lenz effect together with the diamagnetic values specific to precious metals in order to tell genuine gold and silver bars or coins from magnetic fakes.

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

Sigma Metalytics is a product line of handheld testers that measure the specific resistivity of precious metals by electromagnetic induction, reliably exposing counterfeits.

The streak test is a classic chemical method for determining the fineness of gold alloys, in which a streak of metal drawn on a touchstone is compared using 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 almost identical density of tungsten (19.25 g/cm3) and gold (19.32 g/cm3).

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

A non-destructive analytical method that uses X-rays to determine the elemental composition of precious metals and alloys with high precision.