Do you know why some rings turn your finger green, black, or red? Does it mean the metal is cheap? Can the mark hurt your skin? Here’s a look at the chemistry of the discoloration and what it means for your jewelry and your health.
- Skin discoloration from jewelry typically is not dangerous or toxic.
- Green comes from copper in the metal.
- Black usually comes from silver in the metal.
- Red indicates irritation, which has a number of causes. It’s best not to wear the item.
- Even expensive jewelry can cause mark.
Why Rings Turn Your Finger Green
A green discoloration comes from a reaction between copper in jewelry and salts, acids, and other chemicals. The reaction forms a green or blue-green patina consisting of copper chlorides, carbonates, sulfides, and/or sulfates. These compounds color skin, but they are not toxic or dangerous. The mark goes away on its own within a few days after you stop wearing the jewelry.
Some jewelry consists of pure copper, which quickly causes green discoloration (unless the metal has been coated). But, alloys also contain copper. For example, sterling silver often contains 7.5% copper. Gold jewelry often contains copper. 10K (karat) and 14K yellow gold are more likely to contain enough copper to change skin color, compared with 18K or 24K gold. Other alloys that can turn skin green include brass, bronze, and pewter.
Low-quality tungsten carbide also leaves a green mark. Here, the source is cobalt. Many people react to cobalt, too, so a red mark is also possible. Tungsten carbide made using nickel usually does not cause a mark because the nickel integrates into the crystal matrix better than cobalt.
Why Rings Turn Your Finger Black
Black discoloration is essentially silver tarnish transferring onto your skin. Tarnish forms when silver reacts with hydrogen sulfide or sulfur dioxide in air, acids, or with oxygen. Metals high in silver are sterling silver and gold. Silver plating over base metals is common, too.
Often, the black mark comes from tarnish already on the jewelry transferring to skin. Silver rarely leaves a mark when it’s worn all the time. Problems arise when you store it improperly and then wear it. So, keep silver jewelry sealed away from air and moisture, particularly if the air is high in pollution.
Why Rings Turn Your Finger Red
Getting a red mark from wearing a ring or other item indicates irritation. You may have trapped lotion, sunscreen, or perspiration between the metal and skin or may react directly to the metal with an allergy or contact dermatitis.
Nickel and chromium cause the most problems, but some people experience reactions to other metals. The precious or noble metals (e.g., platinum, gold, silver) are less reactive and less likely to cause redness. But, precious metals are usually alloyed with other elements to improve hardness and wear.
Learn about the science of mood ring colors and whether the colors really indicate your emotions.
How to Keep Your Ring From Turning Your Finger Green
Prevent discoloration by coating the inside of a ring with jeweler coating or clear nail polish. The coating wears off over time and requires periodic re-application. It does not harm the metal and acts as a barrier between your skin and the ring.
If you don’t coat your ring, minimize the chance of it turning your finger green or black. Remove rings before bathing, washing dishes, swimming, or applying lotion. Rinse jewelry after exposure to salt water or other chemicals.
Another option is only wearing jewelry that won’t discolor. Stainless steel, platinum, and white gold are the metals least likely to leave marks. Rhodium and platinum coatings don’t cause discoloration. Brass, bronze, copper, and sterling silver often leave marks. Gold sometimes leaves a mark.
Do Only Cheap Rings Turn Your Finger Green?
Inexpensive jewelry usually contains copper and nickel, so it may discolor skin. Unfortunately, even expensive jewelry can leave a mark. This includes genuine gold jewelry. White gold is less likely to turn your finger colors than yellow gold because it often has a plating of rhodium. While sterling silver turns skin black or green, high-end pieces often have platinum or rhodium coatings.
Do You Have Low Iron If a Gold Ring Turns Your Finger Black?
You may have heard about the “gold jewelry test” for detecting low iron or anemia. This is not an accurate test for an iron deficiency. Basically, it’s because so many other things can cause the black mark.
Iron deficiency often causes pruritis or itching. This makes irritation from any jewelry more likely, which often manifests as a red mark. The red mark can transition into a black mark. If the irritation leads to a pH change or if you soothe itching with lotion, metals react and form oxides. If the metal is gold and it turns your finger black, it’s usually from silver in the alloy. But, this happens from a number of causes, such as cutting onions (which contain sulfur) while wearing your ring, perspiring, or swimming in a pool. The odds are low that a black mark signifies iron deficiency. Similarly, you can be anemic and have no marks from jewelry.
References
- Bains, S.N.; Nash, P.; Fonacier, L. (February 2019). “Irritant Contact Dermatitis”. Clinical Reviews in Allergy & Immunology. 56 (1): 99–109. doi:10.1007/s12016-018-8713-0
- Fitzgerald, K.P.; Nairn, J.; Atrens, A. (1998). “The chemistry of copper patination”. Corrosion Science. 40 (12): 2029–2050. doi:10.1016/S0010-938X(98)00093-6
- Mowad, C.M. (July 2016). “Contact Dermatitis: Practice Gaps and Challenges”. Dermatologic Clinics. 34 (3): 263–267. doi:10.1016/j.det.2016.02.010
- Watt, Susan (2003). “How silver reacts”. Silver (Elements). Tarrytown, NY: Marshall Cavendish. ISBN 0-7614-1464-9.