Does gold tarnish?

Pure gold doesn't tarnish. It's one of the most chemically stable metals there is, which is part of why ancient gold artefacts can still look bright after thousands of years. That said, most gold jewellery isn't pure gold, and the other metals mixed in to make it durable enough to wear are a different story. When a "gold" ring or chain looks dull or discoloured after a while, it's usually those alloy metals reacting, not the gold itself.

Here's what's actually going on, and what you can do about it.

Why pure gold doesn't tarnish

Gold is chemically inert, meaning it doesn't react easily with oxygen, moisture or most everyday substances. This is what sets it apart from metals like iron, which rusts, or silver, which tarnishes when exposed to sulfur in the air. In its pure, 24 carat form, gold simply doesn't undergo the kind of chemical reaction that causes tarnishing.

So why does some gold jewellery look tarnished?

Pure gold is quite soft, so most jewellery is made by alloying it with other metals such as copper, silver, zinc or nickel, which add strength and can also affect colour. These additional metals don't share gold's chemical stability, and over time they can react with air, moisture, sweat or certain chemicals, creating a thin surface film that makes the piece look duller, darker or slightly discoloured.

It looks like the gold has tarnished, but really it's the other metals in the alloy doing the reacting, while the actual gold content underneath stays exactly the same.

Does carat affect how much a piece tarnishes?

Generally, yes. The lower the carat, the higher the proportion of non-gold metals in the alloy, and the more likely a piece is to show this kind of surface change over time.

• 9ct gold is 37.5% gold, with the remaining 62.5% made up of other metals, making it more prone to surface discolouration
• 14ct gold is 58.3% gold, sitting somewhere in the middle
• 18ct gold is 75% gold, with noticeably less alloy content and better resistance
• 22ct and 24ct gold contain 91.6% and 99.9% gold respectively, and rarely show any tarnishing at all

This is also why older, lower carat pieces are more likely to need the occasional clean than high carat jewellery of the same age.

What actually triggers this kind of discolouration?

A few common culprits tend to be behind it:

• Chlorine, found in swimming pools and some household cleaning products, which can react with the metals in a gold alloy
• Sulfur-containing substances, including some cosmetics, rubber and certain foods
• High humidity, which speeds up surface reactions over time
• Perfume, lotion and hairspray, particularly when applied after jewellery is already on, leaving residue in direct contact with the metal
• Individual skin chemistry, since sweat varies in acidity from person to person, which can affect how quickly a reaction builds up

Is this the same as white gold losing its shine?

Not quite. White gold typically gets its bright finish from a thin rhodium plating rather than from the gold alloy itself, and when that plating wears thin, the piece can take on a duller or slightly warmer tone underneath. It's a related issue in the sense that it changes how a piece looks over time, but it's down to worn plating rather than the alloy reacting in the way described above.

How to help prevent tarnishing

A few simple habits can keep gold jewellery looking its best for longer:

• Store pieces separately in a soft pouch or lined box, away from open air and moisture
• Remove jewellery before swimming, showering or using household cleaning products
• Apply perfume, lotion and hairspray before putting jewellery on, rather than after
• Wipe pieces with a soft, dry cloth after wearing them to remove sweat and everyday residue

Does tarnishing affect the value of gold jewellery?

No, not in any meaningful way. A duller or slightly discoloured piece still contains exactly the same amount of gold it always did. Our specialists assess every item based on its actual weight and purity, not on how shiny or polished it looks when it arrives.

If you've got jewellery that's lost its shine over the years, feel free to get in touch.

With over 33,000 Trustpilot reviews, we aim to keep the process straightforward, whatever condition your jewellery is in. If you've got questions about how items are assessed before an offer is made, our FAQs page covers many of the most common ones.

A tarnished look might just mean a piece needs a gentle clean, or it might be a sign it's been sitting unworn for a while. Either way, requesting a free postage pack is a simple way to find out what it's actually worth.