If I put a brass ring on my finger and wear it for a couple hours, there will be a green stain on my finger. Copper rings sometimes leave a dark stain on my finger. If I wear a sterling silver ring, I never had that problem. But some people (and it's not really that common) can experience the green finger phenomena with sterling silver and even low karat gold alloys. That does not mean the ring is cheap. It just means that person reacts to the metal in some way.
It usually has something to do with the person's body chemistry. Most likely they have a natural high acidity level in his/her skin. The green finger will happen more likely in hot and humid weather conditions. Once they sweat, a chemical reaction starts between the metals in the ring and the humidity surrounding it. As a result oxides will form. Those oxides are on the surface of the ring and rub off onto your skin leaving a greenish or dark stain. The stain is harmless and non-toxic. It can be washed off with soap and water. But if you actually experience a red itchy rash under your ring, it points to an allergy and should be taken more seriously that the harmless green stains. If you experience a rash, remove the jewelry, get it thoroughly (professionally) cleaned and let the skin heal up before wearing it again. If it persist consult a doctor to find the cause.
If your ring is tight or quite wide (or stacking rings) there is a bigger chance you encounter this issue as moisture is more likely to be trapped on the inside of your ring. Your skin does not get a chance to dry under tight, wide or stacked rings. Washing your hands with your rings left on, not rinsing well and drying afterwards the ring and the skin under the ring, bears a bigger risk too.
|Many stacked silver rings|
Similar chemical reactions can also be caused by ingredients in soaps and lotions. Those are often a culprit for rashes too as soap scum gets trapped between your skin and the ring metal. It's always best to take your ring (or all jewelery off) before showering, washing hands, dish washing and other activities involving exposure to water especially swimming in pools or salt water.
So why can you get the green stain from some sterling silver rings and not others you may ask?
Well, they may fit differently. A more loose fitting ring might not cause that little micro climate and resulting stain from oxidation. Try wearing your ring on a different narrower finger for a couple days and see if the problem persists.
Another reason could be the composition of the metal alloy.
Not all sterling silver is treated equally. All the name sterling silver says is that there is a minimum of 925 parts of pure silver in 1000 parts of alloy. The rest is most often copper. But there are also some newer alloys replacing some of that copper with germanium, zinc, palladium or platinum to increase strength, to reduce tarnish and firescale, or for better casting properties.
Your sterling silver jewelry is usually marked with a 925 stamp on the inside, referring to the silver content. But that mark does not say anything about the other 7.5% metals. Some people, who have issues with the traditional 7.5% copper sterling silver alloy, may be perfectly fine with some of the newer alloys or vice versa.
Low karat gold like 9k, 10k or even 14k can cause the green or black stains too as the lower oxidation resistant gold content is offset by a higher base metal content like copper. All gold alloys contain copper in various percentages. If your skin reacts to copper, you may experience issues with gold alloys too. The higher the gold content the less likely any reactions occur.
Reactions to palladium (950PD) or platinum alloys are very, very rare.
Can a Rhodium plating solve the issue?
Well maybe, but there are drawbacks to consider too.
Artisanal handmade sterling silver rings are rarely rhodium plated. But most commercial mass produced sterling silver jewelry available in malls is rhodium plated these days. It's very a thin layer of an expensive metal, Rhodium, coated over a base substrate, in this case sterling silver. It prevents silver jewelery from tarnishing, which is why it's so commonly used in these retail settings. Can you imagine how much time a sales person would have to spend polishing all that sterling silver jewelry sitting in their show cases to keep it shiny white looking? Rhodium is also a quite hard metal and can give jewelry made from softer sterling silver an initial advantage when it comes to scratch resistance. It also gives it a similar look like plated white gold jewelry at a lower price. So sounds great, right? Well not so fast.
That thin layer of rhodium will wear off over time. It may be a great solution for necklaces or earrings that don't get the rubbing action a ring gets. But on rings, especially those worn daily like engagement or wedding rings, that Rhodium layer can come off quite fast. How fast depends on the layer thickness and each persons wear and body chemistry. Some people can strip a plating within days or weeks, for others it may hold for a couple month or even a year or two. But it will eventually always wear off. And when it does come off, it won't look pretty as it wears unevenly. Rhodium plating does not age well. It may look blotchy and get scratches exposing the different material underneath in some parts more than in others. That material underneath is not necessarily nicely white polished sterling silver. The silver below may have a different texture than the plated surface and tarnishes.
The layer thickness of the plating may vary widely from one manufacture to another. Some just do a flash plating job that won't last more than a few weeks at all. Often rhodium plating isn't directly done over sterling silver but plated with a layer of nickel first. When the rhodium wears off, your skin gets exposed to nickel, which causes skin allergies with nasty rashes for quite a lot of people. So you may have avoided your harmless green stain issue and got a nasty red rash instead some time later. A Rhodium allergy is unusual, but possible too.
Sure you can try to get your ring re-plated as soon as it starts wearing off. But that process isn't cheap and you will pay quickly more in these re-plating jobs that your sterling silver ring cost you initially.
It's also a pain to do any repair work on plated rings as the plating first needs to get stripped before it gets sized or repaired, adding cost to the process. Refinishing a plated ring is also not as easy as repolishing a un-plated sterling silver ring. The normal polishing action on a polishing wheel would just strip the thin layer of rhodium off.
For these reasons I don't recommend rhodium plating for high wear jewelry like rings. It ends up being more a pain than it's worth.
So what can you do if you experience a green stain from your newly acquired nicely hand made ring you love so much?
- check if it's too tight and traps sweat and moisture underneath, if so ask the maker if they can stretch it slightly for you to provide a better fit
- clean your ring and skin well and keep both dry, don't wear it when being exposed to water like showering, hand washing, swimming etc. Remove rings at night to give your skin a chance to breath.
- change your diet so your skin is less acid (probably note everyone's first approach)
- clean the inside of the ring as often as possible (daily) with polishing cloth. After about a week or two, the reaction should stop occurring.
- try soaking your rings in a mixture of household ammonia and water (50/50) for a day or two. The ammonia solution will turn blue as it forms a copper ammonia ion and this will not hurt the silver. After that, your rings will not turn your skin green because the copper has been removed from the surface of the sterling. Be careful if you have any stones set in your rings. Some stones should not be soaked in ammonia.
- consider if Rhodium plating may be worth it for you with all the maintenance issues it may have
- apply a protective shield like clear nail polish to the inside of your ring. It will wear off over time and has to be redone.
- if all does not help consider remaking the ring in a different metal. Platinum, palladium and 18k gold are safe options but come at a higher price. Or use some of the new silver alloys like Argentium, Continuum, deox-silver, palladium sterling or platinum sterling.
If you want to learn more about the metals I use feel free to check out this post.
How to clean your rings see info on my web site.
For more detailed info about sterling silver in general check out a post I co-wrote on EtsyMetal's blog.