Collectors
- Pure 24k gold does not tarnish. It does not oxidise or react with sulphur compounds under ordinary conditions.
- Karat gold is an alloy, and the non-gold fraction is what reacts: 14k is 41.7 percent other metal, 18k is 25 percent, 10k is 58.3 percent. Lower karat means more alloy and more potential to darken.
- The culprits are sulphur compounds, chlorine, perspiration, and cosmetics. Chlorine is the worst — it can embrittle gold alloys over repeated exposure, not just discolour them.
- Most "tarnish" on karat gold is not tarnish at all but film — soap, lotion, and skin oil — and washes off.
- Plated, vermeil, and gold-filled pieces do not tarnish until the gold layer wears through; what tarnishes then is the base metal underneath.
Why Pure Gold Does Not Tarnish, and Why Your Jewelry Is Not Pure
Tarnish is a surface reaction between a metal and something in its environment — for silver, it is sulphur compounds in the air producing a dark silver sulphide layer. Gold is chemically inert under ordinary conditions: it does not react with oxygen, and it does not react with the sulphur compounds that attack silver. That is not a marketing claim but the reason gold has been used as money for millennia. A 24k object will not tarnish, full stop.
Jewelry gold is alloyed for hardness and colour, and the karat number tells you how much of it is gold. 24k is pure; 18k is 75 percent gold; 14k is 58.3 percent; 10k is 41.7 percent. The remainder is commonly copper, silver, zinc, nickel, or palladium, in proportions that set the colour: more copper gives rose gold, white metals give white gold. Every one of those alloy metals can react with something, and the lower the karat, the more of them there are on the surface to do it. Our 14k vs 18k gold guide covers the trade-off in full.
What Karat Gold Reacts With
The same sulphur compounds that blacken silver can darken the silver and copper in a gold alloy, though far more slowly and far less dramatically — the result on karat gold is usually a faint dulling or a slightly darker tone rather than the black of neglected sterling. Sources include polluted air, some foods, rubber, and some cosmetics. Perspiration and lotions add salts and acids and are why the inside of a ring band changes before the outside.
Chlorine is the exception that deserves its own line. Pool and hot-tub water, and bleach, attack the alloy metals in gold, and with repeated exposure chlorine can do more than discolour — it can embrittle a gold alloy through stress-corrosion cracking, which is how a ring that looked fine develops a cracked prong. Take gold off before swimming and before cleaning with bleach. This is the one rule in this guide that protects the structure of the piece, not just its colour. Our guide to how to clean gold jewelry deals with what to do once the damage is only cosmetic.
Fresh water does nothing to karat gold. Salt water is a milder problem than chlorine — salt residue dulls the surface and, left on lower-karat pieces over time, can pit the alloy — and it rinses off with fresh water.
Yellow, Rose, and White Gold Behave Differently
Yellow gold at 14k or 18k is the baseline: slow, faint, and mostly reversible with a wash. Rose gold carries a larger share of copper in its alloy, which is what makes it pink, and copper is the alloy metal most willing to react — so rose gold of the same karat is somewhat more prone to darkening at the edges than yellow. Many wearers like the effect and call it patina; either way it is the copper, not the gold.
White gold is a different case entirely. It is yellow gold alloyed with white metals and then usually plated with rhodium to make it properly white. Rhodium does not tarnish, but it wears, and when it thins at the contact points the alloy underneath shows through faintly yellow or grey. That is plating wear, not tarnish, and the remedy is re-plating rather than cleaning. If your white gold has gone warm-toned on the inside of the band, that is what has happened.
The Green Finger Question
A green or dark mark on the skin under a ring is the alloy or base metal — most often copper — reacting with the acids and salts in perspiration, or with a lotion or soap, and leaving a coloured compound on the skin. It is usually harmless and washes off; a rash or itching is a different matter and points to an allergy, most often nickel. It is more common with plated jewelry, where the base metal is close to the surface, and with lower-karat gold, which has more copper in it; it also varies from person to person, because skin chemistry varies.
It is not, by itself, evidence that a piece is fake. A solid 10k or 14k ring can leave a mark on the right person on a humid day, and a plated ring can leave none on someone else. If the mark bothers you, higher karat, a rhodium-plated finish, or simply taking the ring off to wash your hands can all reduce it. For the question of whether the piece is what it claims to be, see how to tell if gold is real, which covers hallmarks and tests rather than skin.
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Plated, Vermeil, and Gold-Filled Are a Different Question
On a plated, vermeil, or gold-filled piece the surface is real karat gold and behaves like it — it does not tarnish. What changes is what happens when the gold layer wears through at a friction point: the base metal underneath is exposed, and brass, copper, or sterling silver all tarnish readily. A plated piece can reach that point quickly; gold-filled carries many times more gold and lasts far longer; vermeil sits between, over a base that is at least a precious metal. Our explainer on gold filled vs gold plated sets out the legal definitions and the wear difference.
The practical rule for all three is the same: no soaking, no polishing cloths, no abrasives, because every one of those thins the layer that is doing the protecting. A soft dry cloth after wear, and storage away from rubber and other sulphur sources, is the whole routine.
Tarnish vs Film: Which One You Actually Have
Most gold that looks dull is not tarnished. It is coated — soap film, hand cream, skin oil, hairspray — and it washes off in warm water with a drop of mild dish soap, a soft brush, and a rinse. If a wash brings the colour back, it was film. If a faint darkening remains, especially on rose gold or in the recesses of a textured piece, that is the alloy reacting, and a jeweler's polish or a gentle polishing cloth on solid gold will lift it. The cleaning routine, and the exceptions for stones and plating, are in how to clean gold jewelry.
Storage does the rest: separate soft pouches so pieces do not scratch each other, away from rubber and other sulphur sources, and a wipe with a soft cloth before they go in. Solid karat gold stored that way will look the same when it comes out as when it went in, which is the point of buying it.
Now that the background is clear, the buying guide is here: Best Gold Hoop Earrings (2026).
Frequently Asked Questions
Does real gold tarnish?
Pure 24k gold does not tarnish; it does not react with oxygen or with the sulphur compounds that darken silver. Real gold jewelry, though, is an alloy — 14k is 58.3 percent gold — and the copper, silver, and other metals in the alloy can darken slightly over time. That faint darkening is the alloy reacting, not the gold, and it is usually reversible.
Does 14k gold tarnish?
It can darken faintly over time, because 41.7 percent of a 14k piece is alloy metal that reacts with sulphur compounds, perspiration, cosmetics, and above all chlorine. It does not tarnish the way silver does. Most dullness on 14k is soap and skin-oil film that washes off; a persistent faint darkening is the alloy and a jeweler's polish removes it.
Does 18k gold tarnish?
Less than 14k, because 18k is 75 percent gold with only 25 percent alloy on the surface to react. It is not immune — chlorine and sulphur compounds still affect the alloy fraction — but darkening is slower and fainter. The trade-off is that 18k is generally softer and marks more easily, which is a separate issue from tarnish.
Why does gold turn my finger green?
The alloy or base metal — most often copper — reacts with perspiration, lotion, or soap and leaves a usually harmless coloured compound on the skin. It is more common with plated jewelry and lower-karat gold, and varies with the wearer's skin chemistry. A green mark does not by itself mean the gold is fake; a solid 14k ring can do it on a humid day.
Does gold tarnish in water?
Fresh water does nothing to karat gold. Chlorinated water — pools, hot tubs, bleach — attacks the alloy metals and with repeated exposure can embrittle a gold alloy, so take gold off before swimming. Salt water dulls the surface with residue and can pit lower-karat pieces over time; rinse in fresh water afterwards.
Does gold plated jewelry tarnish?
The gold layer does not tarnish, but plating is thin and wears through at friction points, and the base metal underneath — brass or copper — then darkens quickly. Gold-filled pieces carry far more gold and last much longer before that happens. Neither should be soaked, polished, or brushed; a soft dry cloth is the routine.
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How We Research
Our guides draw on manufacturer documentation, established industry practice, and what we learn researching products and listings for our buying guides. Where practice varies or opinion divides, we say so rather than pretending at consensus.
Funding note: This page contains no affiliate links and earns nothing. The karat percentages match the FTC's fineness definitions and this site's other gold guides; the chemistry is general and stated without figures we cannot source, which is why you will find no claim here about how many months or years a given piece takes to darken.