Ask a metallurgist to explain jewelry metals and you could be listening for a semester. It's a whole field, with its own degrees and shelves of textbooks. Most of that depth doesn't matter when you're standing at a jewelry counter or choosing a pendant, though. What matters is a handful of ideas that keep coming back: what the metal actually is, what it has been mixed with, what the stamp on the back is telling you, and how the piece will age once it's on your skin. This guide walks through those ideas in roughly the order you'll run into them, sticking to the metals you're most likely to meet: stainless steel, copper, brass, silver and gold.
Elements and Alloys: Ingredients and Recipes
Every metal on a jeweller's bench is either an element or an alloy, and nearly everything else in this article hangs off that distinction. Gold, silver, copper and iron are elements, the pure entries you'll find on the periodic table. They start life as ore, rock that gets mined, crushed, heated and refined until the useful metal is separated out. An alloy is what you get when refined metals are deliberately blended together, the way flour, butter and sugar become something none of them are on their own. Brass, bronze, steel and sterling silver are all alloys, and each exists because somebody wanted to change how a metal behaves, whether that meant making it harder, cheaper, a different colour, easier to cast, or more resistant to corrosion.
Once you think of the elements as ingredients and the alloys as recipes, a lot of confusing jewelry language starts to make sense. Two pieces that are both called "gold" or "brass" can feel and wear very differently, simply because they were made from different recipes.
Base Metals: Stainless Steel, Copper and Brass
The affordable end of the spectrum is usually called the base metals. The name fits in two ways, because these metals are cheap and common, and they are also the base layer hiding under a lot of plated jewelry. A gold-coloured ring from a mall kiosk is often brass with a thin skin of gold on top.
Stainless Steel
Stainless steel stands apart from every other metal here because it contains iron, which makes it a ferrous metal, while copper, brass, silver and gold are all non-ferrous. That iron makes it hard, tough, and unpleasant to shape with hand tools. Its resistance to rust comes from chromium in the alloy, which reacts with oxygen to form an extremely thin oxide film over the surface, and that film quietly rebuilds itself if it gets scratched. In jewelry you'll mostly see stainless steel in factory-made chains, findings and body jewelry, where certain grades are chosen because they are well tolerated against the skin.
Copper and Brass
Copper is an element, and it is one of the friendliest metals to work. It's affordable, it moves nicely under a hammer, and it softens readily when heated, which makes it a favourite for learning. Brass is an alloy of copper and zinc, and it comes in many recipes, from reddish blends to the brighter yellow "jeweller's brass" that people buy because it looks like gold without the price tag. Both metals react with moisture, sweat and air, and that is where the famous green finger comes from. The stain is a harmless film of copper compounds that forms when sweat and skin oils dissolve tiny amounts of copper from the surface, and it washes off with soap and water. Because of that, copper and brass tend to shine brightest in pendants, bangles and inlay work, where the metal isn't pressed against skin all day the way a ring is.
Silver: Fine, Sterling and Everything Called "Silver"
Silver comes in two versions you need to know. Fine silver is as close to pure as refining allows, stamped .999, meaning 999 parts silver in every thousand. It's bright and slow to tarnish, but it's also soft enough that a fine silver ring will scuff and bend through daily life. Sterling silver solves that by blending 92.5% silver with 7.5% other metal, traditionally copper, which is why sterling pieces carry a .925 or 925 mark. The copper makes the metal much stronger and more practical, and it is also the reason sterling darkens faster than fine silver.
That darkening is worth understanding, because it isn't quite the rusting people imagine. The grey-black film on silver is mostly silver sulfide, formed when silver reacts with sulfur compounds in the air. Sterling picks up copper sulfide as well, since its copper gives the environment one more thing to react with. A polishing cloth works by wiping away that thin layer, and you can read more about why each metal tarnishes in our guide to jewelry metals and tarnishing. If you'd rather tarnish less often, there are tarnish-resistant sterling alloys too. Argentium is the brand most North Americans know, and it uses a little germanium to slow the reaction, but tarnish-resistant still doesn't mean tarnish-proof.
Be wary of names that borrow the word silver without delivering any. Nickel silver contains no silver at all; it's a copper, nickel and zinc alloy that just happens to look silvery. Craft wire sold as "silver" often describes the colour rather than the metal, and "Mexican silver" can mean anything from genuine sterling to lower-grade silver to something mysterious. When a label describes colour or tradition instead of content, the safest move is to buy from a seller who can tell you exactly what the piece is made of. Everything in our gemstone and sterling silver rings collection, for example, is listed with its metal.
Gold: Karats, Colours and Why Pure Isn't Always Better
Gold purity works on the same parts-of-a-whole idea as sterling, except it counts in 24ths instead of thousandths. Twenty-four karat gold is pure, which in practice means about 99.9% gold. Eighteen karat is 18 parts gold in 24, or 75%, and it is often marked 750. Fourteen karat works out to about 58.3% (marked 583 or 585), and ten karat is about 41.7% (marked 417, or .416 in Canada). The higher the number, the more of the piece is actually gold, and the more the rest of the recipe fades into the background. Our karat system explainer goes through the maths and the regional marks in more detail.
Pure gold is gorgeous but soft, and a 24K ring will dent from surprisingly ordinary knocks, which is why most jewelry gold is alloyed down to 18K, 14K or 10K. Those lower karats are tougher, but they also bring more of their other metals to the surface, so they're more likely to discolour or react with skin than high-karat gold. Pure gold itself shrugs off air, water and sweat; it's the added copper, silver or nickel that does the reacting.
Rose, White and Green Gold
Gold straight out of the ground is yellow, and that is the only colour it comes in naturally. Rose, white and green golds are human recipes. Extra copper pushes the colour toward pink, white metals such as palladium, nickel or silver pale it out, and a silver-heavy blend nudges it toward a greenish yellow. Most white gold is still faintly yellow underneath, so it is usually plated with rhodium for that bright, icy finish, and when the rhodium wears thin the warmer tone shows through. If you want a white precious metal that stays white on its own, platinum is the usual answer.
Reading the Stamp
A quality mark like 925, 14K or 750 is a claim about what the piece contains. In Canada stamping isn't mandatory, but if a dealer does stamp a precious metal article, the mark has to be accurate within tight legal tolerances and be accompanied by a registered trademark, unless the piece carries a UK hallmark or a recognised foreign government mark. Canada allows gold to be quality-marked from 9K up; in the United States, 10K is the lowest that can be sold as karat gold. The catch is that a stamp is only as honest as whoever applied it. Steel punches reading 925 or 14K can be bought online for a few dollars, so a mark on an unknown piece is a starting point for questions, not a guarantee.
Plating, Rust, Tarnish and Patina
Plating is a thin coat of one metal over another, usually gold or rhodium over brass, bronze or silver. Typical jewelry plating is roughly a micron thick, a thousandth of a millimetre, and a quick "flash" plate is thinner still, which is why plated rings and bracelets wear through on the high spots first. Some makers add a clear e-coat, a fine polymer film that takes the wear before the gold does. Our article on plating versus filled metals covers how long each option tends to last.
It also helps to keep four words straight. Rust is iron corroding, and it eats into the metal itself. Tarnish is a surface film, like the sulfides on silver, and it polishes away. Patina is the broader colour change that copper-rich metals and silver develop over time, and jewellers sometimes bring it on deliberately with liver of sulfur to darken recesses and make texture pop. Sweat, coastal air and anything acidic speed all of this up, which is why the same sterling chain can stay bright on one person and dull within weeks on another. When it's time to brighten a piece, our jewelry cleaning and polishing guide walks through safe methods for each metal.
Choosing a Metal That Suits You
For a ring or earrings worn every day, sterling silver, 14K or 18K gold, or platinum will treat your skin and your wallet more fairly than mystery metal. Nickel is the most common cause of jewelry allergies, so if you react to cheap pieces, look for nickel-free alloys or well-tolerated stainless steel grades. Copper and brass are wonderful for statement pendants and cuffs, provided you don't mind a little upkeep. Browse all our jewelry, our gemstone, crystal and fossil pendants, or the hand-cast pieces in Broken Ox organic jewelry, like this tree bark pendant cast from real Sitka spruce bark. If you're ready to work metal yourself, start with our silversmithing and jewelry-making tools and fine silver wire. Silver or copper is the most forgiving place to begin.
