The physical properties of various metals

Many of us wear gemstones for their beauty and healing properties. But what about the setting the gemstone goes in, or the chain we wear with it? Often that’s the part closest to your body, and these parts are usually made of metal. And metals have their own individual characteristics and properties. Since it’s a complicated topic, this article will be a two-parter. This week we’ll talk about the physical properties of metals and alloys, and in a few weeks we’ll talk about the metaphysical properties of metals.

Metals may be either one pure element or an alloy, which is a mixture of metals. In jewelry, the latter is far more common. Elemental copper, silver and gold are quite beautiful, but they’re all soft on their own, which means they won’t hold their shape well as jewelry. So an alloying metal is added to make them more workable and stable. Even the types of metal we think of as “pure” may have something else in them; Sterling silver, for example, is actually 7.5% copper. And sometimes even Sterling may contain traces of other metals as well, including nickel.

That can be a problem, because by far the most common metal allergy is to nickel. While some people do suffer from all types of allergies, it’s likely that many allergic reactions to metal are due not to a separate allergy, but to the fact that so many alloys actually contain nickel. So if you have sensitivities to nickel or any other metal, you’ll want to avoid problems by knowing what jewelry is made of before you buy it. Hopefully the charts below is a start, but there are some other things it’s important to know.

One is that metals are sometimes given confusing names. Metals called German Silver, Tibetan Silver, Inca Silver and other such things usually contain no silver at all. And items that look like they’re made of one metal may actually have only a coating of that metal. For example, often something that looks like copper will turn out to stick to a magnet. Copper isn’t attracted to magnets, so this shows the item is really steel with just a coating of copper. The same often holds true for “silver-look” and “gold-look” chains and other items. And some terms, like “white metal,” are simply a catch-all, and can mean just about anything.

Another problem metal is lead, a toxic element that can especially cause problems in children. Since lead makes a very good alloying material, in the past it was often used to make pewter and other mixed metals. Antique pewter jewelry is very likely to contain lead. Nowadays pewter produced in the U.S. is lead-free, but laboratory tests have shown that many inexpensive items currently imported from China — including cheap jewelry — do in fact contain lead. This should be safe enough for adults to wear; still, many of us would rather avoid it. And over-the-counter lead testing kits don’t always work well to test jewelry, since they may give a false positive to non-lead metals used to make safe pewter alloys.

Those of us who staff stores where jewelry is sold will do our best to let you know what kind of metal is in the items we sell. We can be pretty sure about items made of silver stamped 925, American-made pewter, brass and bronze. But in other cases, the truth is that we don’t always know, especially when it comes to lower-priced imported items. A lot of people enjoy wearing these things and have no problems whatsoever. But if you’re sensitive to certain metals (or have a baby that likes to suck on your chains) you’ll probably want to stick to metals whose content is known.

Another thing people ask is, “Will this metal turn my skin green?” Various metals may do this, the most common being copper and nickel — even if they’re coated with something else. For example, a lot of silver-plated chains are really copper with a thin silver plating, and for some people this will turn the skin green every time. But it’s not the same for everyone, and a lot depends of body chemistry. If you find a lot of metal jewelry turns your skin green, your body chemistry may be more sensitive than other peoples’. In that case, your best choices of metal may be things like stainless steel, titanium, an rhodium-coated silver. But there also are plenty of other handsome-looking options that don’t involve metal at all, such as cotton cord, leather, and ribbon. When you do wear metal, try taking off your jewelry when you exercise, or in other situations where the metal may get wet. Sweat causes even pure sterling silver to tarnish, and that tarnish may also stain your skin.