Is iron jewelry safe to wear? What's the difference between cast iron, wrought iron, and steel? If you're looking for a piece of jewelry made from these metals, then this guide will help inform your decision.
Is Iron Jewelry safe to wear?
For the vast majority of us, yes. Very few people have allergic reactions, and those that do are usually alright once they remove the ring or other piece of jewelry.
Outside of an allergic reaction, the worst that happens is the browning of the wearer's skin where the metal is touching them. What I recommend to my customers is first to remove the piece at night before going to bed. After this, I advise taking it off in situations where you know it's going to get wet or they are going to sweat alot. Moisture often makes this happen faster. As far as I know, it's the nickel present in some steel alloys.
The browning is similar to the greening we get from wearing brass pieces. It goes away when the piece isn't worn all the time.
Iron Jewelry vs. Steel Jewelry vs. Wrought Iron Jewely vs. Cast Iron Jewelry. What's the difference?
In the previous section, I mentioned nickel and alloys. This is because pure iron is practically useless for making jewelry. It doesn't have the properties we need for it to hold shape and withstand the forces that daily wear places upon it.
Often, I have customers ask "Is your jewelry iron? I'm looking for an iron anniversary gift."
The short answer is yes. Technically, yes. The longer answer involves a term known as an alloy.
What is an alloy?
It's a compound formed by mixing different metals together. Steel is an iron alloy. Where Iron is the primary constituent (makes up the highest percentage in the final product of metal). Therefore, if someone were to ask "Are your rings made of iron?" the answer is yes. Steel is an iron alloy.
To be precise, I use 304L stainless steel. This alloy contains Carbon, Manganese, Silicon, Phosphorus, Sulfur, Chromium, Nickel, and Nitrogen— in addition to the biggest constituent: Iron.
Cast Iron Jewelry vs. Wrought Iron Jewelry.
To continue with our discussion on alloys, cast iron and wrought iron are both iron alloys.
Cast iron contains 2-4 percent carbon, as well as silicon and manganese. Sulfur and phosphorus are sometimes found as impurities in the alloy. This results in a harder finished product that is more brittle (i.e. holds shape better, but breaks when too much pressure is applied).
Whereas "Wrought iron is composed primarily of elemental iron with small amounts (1–2 percent) of added slag (the by-product of iron ore smelting, generally consisting of a mixture of silicon, sulfur, phosphorous, and aluminum oxides)." 1
Wrought iron is formed by what most of us think of as traditional blacksmithing. Heat, hammer and repeat until its worked into the right shape. Wrought iron is softer and will undergo more deformation before failing. Think bend, not break.
My work falls into the latter category, as I hand forge my jewelry on an anvil with hammers. The reason I cannot honestly classify my work as wrought iron, is because of the alloy that I use.
It may also be important to note that wrought iron could be technically classified as steel if we're going off of the textbook definition: an alloy of iron with carbon and usually other elements.
Which should I get?
Honestly if you're looking for an iron anniversary gift (6th year of marriage) or steel anniversary (11th year) you can get anything made of steel and be good.
If you're a purest, go after wrought iron. Back in the day, our smithing ancestors likely believed they were making pure iron and had no way of removing the impurities left over from the slag and other natural process. Which incidentally gave the iron alloy the properties they desired.
At the end of the day, any artisan can claim "My jewelry is made from iron" and not just get away with it, but also be within their rights if they work with any steel alloy.
My advice is to pick the piece that you want, or that you think communicates the message you're looking for. Because either way, it's pretty much all steel. And all steel is iron. Hopefully this free's up your decision and doesn't add more confusion.
If you have any questions feel free to post them in the comments or reach out directly.
1 - Reliance Foundry - Ask a Metallurgist: Wrought Iron vs Cast Iron