Materials Chemistry

What are wedding rings made of, and how do their properties vary?

Infographic highlighting properties of metals used for wedding rings. Further detail is provided in the text below.
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I’m currently at that age where my Facebook news feed is an endless stream of either wedding or baby photos. Most recently, one of my best friends was shopping for wedding rings in advance of their marriage next year, which got me thinking about different wedding ring metals. What elements are they composed of, and how does this influence their properties?
White metals
Silver, platinum and palladium are referred to as white metals when it comes to jewellery. Silver is the more common of the three, as well as being the least pricey. Silver rings are made from sterling silver, which is an alloy (a mixture of metals). Sterling silver has to contain a minimum of 92.5% of silver. Copper usually makes up the remaining percentage. This alloy is necessary because pure silver is quite malleable – meaning it could bend out of shape over time. Adding copper increases the hardness of the silver and makes it less malleable.
Platinum and palladium rings are on the more expensive end of the wedding ring spectrum. They, too, are not composed of the single metals and are alloyed with other metals to improve their properties. Rings made from these two metals often have a purity of 95%. The remaining percentage is usually ruthenium, iridium, or rhodium. Platinum rings have the highest density of the metals considered in the graphic; this means they feel weightier.
Gold metals
Like silver, pure gold is too malleable to fashion jewellery from. When alloyed with other metals, superior properties can be achieved, along with a range of colours.
Yellow gold maintains the characteristic hue of gold, but silver and small amounts of copper make it suitably resilient. Rose gold also contains copper and silver along with the gold, but the slightly higher amount of copper gives it a coppery hue. White gold, meanwhile, is an alloy commonly composed of gold with palladium or platinum. It has more of a silvery than a golden appearance. This is due to the fact that it’s often plated with rhodium, adding hardness and a silvery shine.
Gold ring purity can be measured in carats. 24-carat gold is 100% gold, which you won’t find in a ring due to gold’s softness. 18-carat gold is more common (75% gold), while 14 carat (58.5%) gold is cheaper due to the lower gold content.
Newer metals
Titanium, zirconium, tungsten and steel are increasingly common wedding ring metals. They have the advantage of being cheaper than metals like gold and platinum, as well as being more durable.
As with the previous metals we’ve examined, though they’re referred to by the name of the main metal they contain, they’re all a mix of metals. Titanium rings are commonly made from aircraft grade titanium, an alloy with small amounts of vanadium and aluminium added. These rings have the lowest density of any of the materials featured in the graphic, meaning they’re particularly light for their size.
Tungsten rings are made from tungsten carbide, a compound of tungsten and carbon which is one of the hardest known materials. If you’ve got a ring made from tungsten carbide, worrying about your ring getting scratched isn’t a thing – if anything, you’re worried about your ring scratching other objects. However, its extreme hardness can also make it prone to shattering.
Tungsten carbide rings also have a small amount of cobalt added to improve their malleability. Cobalt is also a ring material in its own right, though it’s not featured in the graphic; it’s commonly alloyed with chromium.
Black zirconium rings are created by oxidising zirconium metal to produce a black coating of zirconium oxide. This is then polished to produce a smooth, black surface. It has a low density combined with a good hardness that makes it difficult to scratch. Normal zirconium rings are also sometimes seen.
Finally, stainless steel rings are perhaps less glamorous-sounding, but also quite resilient. Steel is an alloy of iron and carbon; stainless steel contains a minimum of 10.5% chromium.
Resizing rings
Some people might go their whole lives without needing to resize their wedding rings, but for others, there may come a time when it needs to be enlarged (or made smaller, for that matter). At this point, the material your ring is made from might determine whether or not that’s possible.
For rings based on the softer metals, like gold, silver, platinum and palladium, resizing is fairly straightforward. For other, harder metals, resizing is more problematic. Black zirconium and tungsten carbide rings are near impossible to resize. While titanium and stainless steel rings can be resized, it’s also quite difficult, and if possible can usually only be changed within limits. Something to bear in mind if you purchase a ring made from these materials!

References & Further Reading

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