Authenticity Testing

The acid test is a chemical method 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 size check measures a coin's diameter and thickness with callipers or a gauge and compares the values with the official minting specifications, in order to expose counterfeits by their deviating dimensions.

The coin weight check is a simple, non-destructive method for verifying the authenticity of precious-metal coins, comparing the actual weight against the manufacturer's official specified weight.

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

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

The ice melt test exploits the exceptionally high thermal conductivity of silver to distinguish genuine silver from fakes: an ice cube melts noticeably faster on a real 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 balance uses the Lenz effect of the metal-specific diamagnetism values to distinguish 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 of a coin when lightly tapped to distinguish genuine precious-metal coins from counterfeits.

Sigma Metalytics refers to a product line of portable testing devices that use electromagnetic induction to measure the resistivity of precious metals and thereby reliably expose counterfeits.

The streak test is a classic chemical method for determining the fineness of gold alloys, in which a metal streak drawn 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 to exploit the nearly 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-rays to precisely determine the elemental composition of precious metals and alloys.