Although the common misconception is only inexpensive jewelry causes discoloration, that is not necessarily true. Both copper and silver are common causes of skin discoloration from rings.
Oxidation can cause metals (except precious metals i.e., Gold, Silver (fine) and the Platinum family) to react with acids in your skin. Sterling Silver is not pure and can oxidize and tarnish which can leave a dark ring on your finger. Additionally, stainless steel, platinum, and rhodium-plated jewelry are less likely to turn green your finger green.
Note: If you have itchiness, redness or a more severe reaction it may be an allergic reaction (as discussed in July’s newsletter).
When a metal ring turns your finger green normally it is a chemical reaction between the metal and the acids in your skin (including sweat) or lotions, etc. To reduce oxidation and the likelihood of a ring turning your finger green ensure you clean your ring (with a soft cloth) before and after wearing it. Moreover, do not use lotion, shampoo, dish soap, hand soaps, etc. with your rings on and remember to remove your rings before swimming (especially in saltwater). Dry your hands before putting your rings back on. If you do have discoloration, it is typically innocuous and cleans off with just soap and water.
The majority of my Fused Glass ring shanks are plated (silver, gunmetal etc.) over a copper base, albeit I do have sterling silver and stainless steel ring shanks as well that you can request for an additional fee. The only time I have had an issue with one of my fused glass rings was when I wore them while working in my studio with various chemicals, definitely not a good idea.
What works best for me is keeping a little dish by the sinks in my studio, bathroom, and kitchen to put my rings in so it is easy to remember to take them off and put them on.
I’m sure you are wondering why I am focused on rings and not pendants or bracelets. The discoloration (chemical reaction) typically occurs when there is little or no air circulation between skin and metal. Normally there is air circulation between a pendant / bracelet and skin. That being said, discoloration may occur so it is best to follow the same rules i.e., remove before swimming / taking a shower and be aware of lotions, etc.
This information came from various internet sites but the majority came from Anne Helmenstine, Ph.D., About.com Guide.
Please let me know if you have any questions.