What is in 9ct gold
Nine parts gold to fifteen parts alloy. Copper adds warmth and hardness, silver lightens the colour, zinc helps casting. The result is paler and harder than higher standards, which is exactly why it suits rings and chains worn every day.
Why Britain uses so much of it
9ct has been a recognised British standard since the nineteenth century and became the default for mass-market jewellery. Most high street chains, signet rings, charm bracelets and gate bracelets sold in the UK over the past century are 9ct — which is why it makes up the bulk of what people find when they clear a jewellery box.
How it wears
- Resists scratching and denting better than 18ct or 22ct.
- Can tarnish slightly over many years because of its copper content.
- Solder joints and thin links still fail with age — common on worn chains.
- Not magnetic. A magnet sticking firmly to a "9ct" chain is a warning sign.
9ct gold and value
Fine gold content is 0.375 grams per gram of item weight, so 20 grams of 9ct holds 7.5 grams of pure gold. Because the alloy metals contribute little, two 9ct items of the same weight are worth much the same as metal regardless of style — unless one has value as a complete piece of jewellery.
What does 375 mean on gold?
375 is the fineness mark for 9 carat gold. It means the item is 375 parts gold per 1,000 by weight, or 37.5% pure gold, with the balance made up of alloy metals such as copper, silver and zinc. It is the most common gold fineness mark found on British jewellery.
Recognising a genuine 375 mark
On a properly hallmarked British item, 375 appears inside a shaped surround, accompanied by a sponsor's mark and an assay office mark. If you can only find the three digits and nothing else, you are probably looking at a manufacturer's stamp rather than a UK hallmark — see UK gold hallmarks explained.
Marks sit in predictable places: inside a ring shank, on a chain's clasp or tag, on an earring post, on the back of a pendant bail. They are struck small and wear down with use, so a partial mark is common on jewellery worn for decades.
375 and 9ct mean the same thing
"9ct", "9K" and 375 all describe the same standard. UK hallmarks use the numeric fineness; makers' stamps often use the carat figure. What matters for valuation is the standard, not which convention was used to express it.
Marks that look similar but are not solid gold
- 9ct GP or gold plated — a base metal item with a microscopic gold layer.
- 9ct GF or rolled gold — a thicker bonded layer, still not solid gold.
- RGP and HGE — rolled gold plate and heavy gold electroplate.
- 925 with a gold colour — sterling silver that has been gold plated, correctly hallmarked as silver.
What 375 means for what you are paid
A 9ct item contains 37.5% gold by weight, so a 10 gram 9ct chain holds 3.75 grams of fine gold. The remaining 6.25 grams are alloy metals of comparatively little value. Buyers work from the fine gold content, which is why weight and purity together — not weight alone — determine the metal value. Work yours out with the gold purity conversion chart.
9ct is the lowest standard that may legally be described and hallmarked as gold in the UK.
Is 9ct worth selling?
Small quantities amount to little; a drawer of broken 9ct chain often amounts to more than people expect, because weight accumulates. Gold Up will weigh what you have and explain how the figure is reached before you decide.
