Short answer: Pure gold doesn't tarnish or corrode. Solid 14k–18k gold resists tarnish very well. Discoloration and green skin almost always come from the alloy metals or base metal — most common with plated pieces and, to a small degree, lower-karat gold like 10k reacting with sweat, lotions, or chlorine.
Why pure gold doesn't tarnish
Gold is a noble metal — chemically it barely reacts with oxygen or moisture, which is why ancient gold artifacts come out of the ground still shining. So the more gold a piece contains, the less it tarnishes. That's why 18k resists discoloration better than 14k, and 14k better than 10k.
What actually causes discoloration
The culprit is the alloy. Lower-karat gold contains more copper and silver, which can react over time — copper can darken, silver can form a faint tarnish — especially when exposed to sweat, perfume, lotions, and chlorine. On plated pieces, the thin gold wears through and the base metal underneath corrodes quickly. So "my gold turned colors" is usually a sign of low karat or plating, not a defect in real high-karat gold.
Why gold turns some people's skin green
Green or black marks on skin come from base metals — mainly copper — reacting with acids and salts in your sweat and with cosmetics, forming compounds that rub off on skin. This is common with plated and costume jewelry and with very high-copper alloys. Solid 14k or 18k gold rarely does it. If a "gold" chain consistently greens your skin, suspect plating or a base-metal core.
How to prevent it
- Take the chain off before swimming (chlorine is hard on gold alloys) and before applying lotion, cologne, or sunscreen.
- Wipe it down with a soft cloth after heavy sweating.
- Clean it periodically with warm water and a drop of mild dish soap — see how to clean a gold chain.
- Buy higher karat (14k+) and solid, not plated, if tarnish and skin reactions matter to you.
Frequently asked questions
Does real gold tarnish?
Pure gold doesn't tarnish. Solid 14k and 18k resist it very well. Lower karats like 10k can show slight discoloration over time because of their higher copper and silver content, and plated pieces tarnish quickly once the gold wears.
Why did my gold chain turn my neck green?
Green skin comes from base metals like copper reacting with sweat and lotions. It points to a plated or base-metal piece, or a high-copper alloy — solid 14k+ gold rarely causes it.
Can you fix a tarnished gold chain?
Surface tarnish on solid gold usually cleans off with warm water, mild soap, and a soft brush. Plated pieces that have worn through can't be restored at home — the gold layer is gone.