Green or dark marks beneath jewelry are usually caused by a reaction involving metal, moisture, cosmetics, or skin chemistry. The mark is often a surface transfer rather than proof of a dangerous reaction, but persistent irritation should be taken seriously.

Why green marks occur

Copper can react with perspiration, lotion, soap, or moisture and form compounds that transfer to the skin. Copper may be present in brass, bronze, sterling silver alloys, rose gold, and some lower-karat gold alloys.

Why black or gray marks occur

• Metal particles can rub from a polished surface and mix with cosmetics or skin oils.
• Silver-containing alloys may tarnish and leave dark residue.
• Powders, lotions, and soaps can act as mild abrasives.
• A plated surface may wear through and expose a different metal beneath.

Is it an allergy?

Color transfer alone is not the same as an allergy. Allergic contact reactions are more likely to involve itching, redness, swelling, blistering, or a persistent rash. Nickel is a common jewelry allergen, although other metals or trapped moisture may also cause irritation.

What can help?

Keep the jewelry and skin clean and dry, remove rings before using strong cleaners, and avoid trapping soap or moisture beneath close-fitting pieces. A jeweler can help identify whether the item is solid, plated, worn, or in need of repair. For ongoing or significant skin symptoms, seek guidance from a qualified healthcare professional.