Silver and nickel are two visually similar metals that cause frequent confusion due to their bright, silvery-white appearance, especially when items lack clear identifying marks. Silver is a precious metal valued for its unique luster, while nickel is a durable base metal often used in alloys or as a plating material. The distinction is significant, impacting value, care, and potential skin reactions. Understanding the fundamental differences in their physical and chemical properties provides reliable methods to determine which metal you possess.
Visual Appearance and Surface Wear
The initial step in identification involves a careful visual inspection of the item’s shine and how its surface has aged. When polished, silver exhibits a soft, cool, and highly reflective white luster, often described as having a mirror-like depth. Nickel, conversely, tends to present a slightly harsher, brighter, or more blue-white shine, sometimes with a subtle yellow or warm gray undertone. This difference is most noticeable under bright, natural light.
Tarnish provides a strong clue. Silver reacts readily with sulfur compounds in the air, creating silver sulfide, which manifests as the familiar dark gray or black tarnish layer. Nickel and its alloys, such as nickel silver, tarnish differently or not at all, often developing a dull, off-white, or sometimes a yellow-green film instead of a uniform black oxidation.
The metal’s hardness also affects its long-term appearance. Silver, especially in its pure form, is a relatively soft metal that scratches and dents easily with regular use. Nickel alloys are substantially harder and more resistant to scratching and surface wear, which may result in a more consistently bright, unblemished surface over time. If a piece has deep, easily acquired scratches, it is more likely to be silver.
Identifying Common Hallmarks and Stamps
The most definitive non-destructive way to identify a manufactured item is by locating and interpreting its hallmark or stamp. These tiny markings are usually found in inconspicuous places, such as on the clasp of a necklace, the inside band of a ring, or the underside of flatware handles. Genuine silver items are legally required in many regions to bear a mark indicating their purity, known as fineness.
Common stamps for solid silver include millesimal fineness numbers. Sterling silver is designated by `.925` (92.5% pure silver). Fine silver is marked as `.999` (99.9% pure), while coin silver is often marked as `.900` or simply `Coin`. Other symbols, such as a lion passant or the word `Sterling`, are also internationally recognized indicators of quality silver.
Items made from nickel-containing alloys or that are merely silver-plated will carry different markings or sometimes none at all. Nickel silver, also known as German silver, contains no actual silver but is an alloy of copper, nickel, and zinc. A common plating mark is `EPNS`, which stands for Electro-Plated Nickel Silver, indicating a thin layer of silver applied over a nickel-based core metal. The presence of any plating mark means the item is not solid silver.
Practical Non-Destructive Home Tests
One quick test is the magnetism test, as silver is a diamagnetic element and is not attracted to a magnet. While pure nickel is ferromagnetic (magnetic), the nickel alloys commonly used in jewelry and flatware are often weakly magnetic or not magnetic at all. If the item is strongly pulled toward a common refrigerator magnet, it is certainly not silver.
Another reliable method is comparing the density (mass per unit of volume). Pure silver has a density of approximately 10.5 g/cm³, while pure nickel is significantly lighter at about 8.9 g/cm³. This means that a solid silver object will feel noticeably heavier than a nickel or nickel alloy object of the exact same size and shape. You can test this by comparing the suspected item’s weight to a known silver piece or by simply assessing its heft.
The skin reaction test offers a definitive way to identify the presence of nickel, which is a common allergen. If the item causes a greenish or black discoloration on the skin, or leads to contact dermatitis, such as a localized rash or itching, it is highly probable that the piece contains a substantial amount of nickel. Sterling silver rarely causes these allergic reactions or skin stains, providing a strong indication of a nickel alloy if a reaction occurs.