Short answer: green skin discolouration happens when a metal, usually copper, which is used to make cheap "gold" and "silver" alloys stronger reacts with sweat, oils, or moisture and oxidises against your skin. It's not an allergic reaction and it's not permanent, but it is a reliable sign that the metal underneath the plating isn't what it claims to be.
What's actually happening
Pure gold and pure silver don't turn skin green. The green comes from copper, which is mixed into most "gold" and "silver" jewellery to make it more durable and affordable to produce. When that copper alloy sits against warm, slightly acidic skin especially with sweat or lotion involved it oxidises, and the resulting compound (copper oxide, essentially the same chemistry as a tarnished penny) transfers onto your skin as a green or grey tint.
Gold-plated and silver-plated jewellery is particularly prone to this because the plating layer is often just a few microns thick. Once it wears, usually within weeks of regular wear you're left wearing the copper-alloy base metal directly against your skin.
Why it's worse in some conditions than others
- Humidity and sweat accelerate the reaction, which is why green ears are more common in summer or after workouts
- Perfume, hairspray, and lotion applied near the ears introduce more chemicals for the metal to react with
- Swimming or showering in jewellery not designed for water exposure is one of the fastest ways to trigger it
How to actually avoid it long-term
The only real fix is wearing jewellery that doesn't contain reactive base metals in the first place not thicker plating, which just delays the problem. 316L stainless steel doesn't contain copper in a form that oxidises this way, and because it's a solid alloy rather than a plated layer, there's no thin coating to wear through and expose the metal underneath.
If you've noticed green ears from pairs you assumed were "real" gold or silver, it's worth checking whether they're solid or plated. A quick way to tell is checking if any stamped hallmark specifies karat or fineness (like 14k or 925). If there's no hallmark at all, it's very likely a base-metal alloy, and the green tint will keep coming back no matter how you care for it.
