When examining silver coins, a common question is whether they are magnetic. Many wonder if real silver reacts to a magnet, as understanding this can offer initial insight into a coin’s composition.
Silver’s Non-Magnetic Properties
Pure silver is not magnetic. It is a diamagnetic material, meaning it exhibits a very weak repulsion to a magnetic field rather than an attraction. This slight repulsion occurs because electrons within silver’s atoms adjust their orbital motion to create a magnetic field opposing the external field. However, this diamagnetic effect is so subtle that it is typically imperceptible without highly sensitive laboratory equipment or very strong magnets. A common household magnet will not stick to a pure silver coin.
Understanding Metal Magnetism
The magnetic behavior of metals depends on their atomic structure and electron configuration. There are three types of magnetic responses: ferromagnetism, paramagnetism, and diamagnetism. Ferromagnetic materials, such as iron, nickel, and cobalt, exhibit a strong attraction to magnets because their atomic magnetic moments spontaneously align. Paramagnetic materials, like aluminum or platinum, have unpaired electrons that create weak magnetic moments, resulting in a slight attraction to a magnetic field. This attraction is generally too weak to be noticed with a common magnet and disappears once the external magnetic field is removed. In contrast, diamagnetic materials, including silver, copper, and gold, have all their electrons paired. When exposed to a magnetic field, these materials generate a weak opposing field, leading to a slight repulsion not observable in everyday situations.
Testing Coins with a Magnet
A simple magnet test offers a preliminary indication of whether a coin is likely pure silver. If a coin strongly sticks to a magnet, it is almost certainly not pure silver, as it likely contains ferromagnetic metals like iron, steel, or nickel. Many counterfeit or silver-plated items use these magnetic core materials.
Conversely, if a coin shows no attraction, it could potentially be silver, but this is not definitive proof of authenticity. Many non-magnetic metals, including copper, zinc, lead, and aluminum, also do not stick to magnets. While very strong neodymium magnets can sometimes reveal silver’s weak diamagnetic properties through a slow sliding motion on an inclined surface, this test is not foolproof and requires careful interpretation. Therefore, while the magnet test can rule out pure silver if a coin is attracted, it should be combined with other verification methods, such as weight, specific gravity, or sound, for a more conclusive assessment.