Magnetism describes the force that causes certain objects to attract or repel each other. This phenomenon arises from the movement and alignment of electrons within a material’s atomic structure. Not all metals interact with magnets in the same way; some are strongly attracted, others are weakly affected, and many show no noticeable reaction at all. Understanding the magnetic properties of metals used in jewelry can provide insight into their composition and characteristics. This article explores which common jewelry metals are not magnetic and why.
Naturally Non-Magnetic Jewelry Metals
Many popular metals used in jewelry are inherently non-magnetic in their pure forms. Gold, for instance, is a diamagnetic metal, meaning it weakly repels magnetic fields, though this effect is imperceptible in everyday scenarios. Pure 24-karat gold is consistently non-magnetic and widely used in various jewelry pieces.
Silver, another widely used precious metal, also exhibits non-magnetic properties. High-quality silver, such as sterling silver (92.5% silver), remains non-magnetic, even though alloys can sometimes introduce magnetic characteristics. Like gold, pure silver is diamagnetic, causing a slight repulsion to magnetic fields.
The platinum group metals, including platinum, palladium, rhodium, iridium, ruthenium, and osmium, are generally non-magnetic. Platinum, a popular choice for high-end jewelry, is typically non-magnetic, though some platinum alloys might contain small amounts of magnetic metals. Palladium, another member of this group, is also non-magnetic. Titanium, a strong and lightweight metal increasingly favored in modern jewelry, is also recognized for its non-magnetic quality.
Metals That Can Be Magnetic in Jewelry
While many precious metals are non-magnetic, certain metals are strongly magnetic and can appear in jewelry, primarily as components of alloys. Iron is a ferromagnetic metal, meaning it exhibits strong, permanent magnetism. Although pure iron is not typically used for fine jewelry, it is a significant component in many common alloys, including various types of steel.
Nickel is another metal known for its magnetic properties and its frequent inclusion in metal alloys. For example, nickel is often used in white gold alloys, which can sometimes result in a slight magnetic response if the nickel proportion is higher. It is also present in some stainless steels.
Stainless steel itself can display varying magnetic properties depending on its specific composition and crystalline structure. Some types, like ferritic and martensitic stainless steels, are generally magnetic due to their higher iron content. Other types, such as austenitic stainless steel (e.g., grades 304 and 316L), are typically non-magnetic because they contain higher levels of nickel and chromium, which alter their atomic structure.
How Alloys and Purity Affect Magnetism
The magnetic behavior of a jewelry piece is significantly influenced by its composition, particularly when it is an alloy. An alloy is a mixture of two or more metals, or a metal combined with other elements. The addition of even a small percentage of a magnetic metal to an otherwise non-magnetic base can introduce magnetic properties to the entire piece.
For instance, while pure gold is non-magnetic, lower-karat gold alloys (such as 10K or 14K) may exhibit slight magnetism. This occurs because these alloys contain higher proportions of other metals, like iron, nickel, or cobalt, which are magnetic. The higher the purity of gold, such as 24-karat, the less likely it is to contain magnetic components, ensuring it remains non-magnetic.
Even non-magnetic austenitic stainless steel can become slightly magnetic if it undergoes cold working or certain manufacturing processes. A simple magnet test can sometimes indicate the presence of magnetic alloy components, but it is not a definitive test for purity or authenticity, as many genuine non-magnetic alloys exist.