Published 2 June 2026
The number explained
375 is parts per thousand. Out of every 1000 units of the alloy by weight, 375 units are pure gold. That works out to 9 parts of gold in a 24-part system, which is where the "9 carat" name comes from. The other 625 parts are partner metals that give the alloy its colour, hardness and machinability.
A common 9ct yellow recipe is roughly 37.5% gold, 42% silver and copper in varying ratios, with the remainder as zinc. A common 9ct white recipe substitutes palladium or nickel for the silver to neutralise the yellow tone.
Why 9ct is so common in the UK
The result is that any postal buyer in the UK sees more 9ct in a typical parcel than every other karat combined. Chains, rings, charm bracelets, lockets and signet rings are dominated by the 375 mark.
Hardness and wear
9ct is harder than 18ct or 22ct because the partner metals (copper, silver, zinc, sometimes palladium) make the alloy stiffer. A 9ct band will resist denting and scratching better than a high-karat band of the same shape. That is why working hands often prefer 9ct for everyday rings.
The trade-off is colour. 9ct yellow is a paler, slightly cooler shade than 18ct yellow. Some buyers prefer the deeper warmth of higher karats. The colour preference is personal. The scrap economics are decided by the karat number, not the shade.
How 9ct sells at scrap
9ct is the most liquid scrap category in the UK. Refiners process huge volumes of it, the recovery process is well established, and pricing tracks the live market without unusual margins. The recovered yield per gram is lower than higher karats because the gold percentage is lower, but the per-gram efficiency from the refiner side is excellent.
Final offers depend on inspection, item weight, purity, hallmarks, stones, non-gold components, condition and the live precious-metal market.
Identifying 9ct quickly
- Find the inside of the shank or the clasp.
- Look for "375" inside a shield punch, or "9ct" in older stamping styles.
- Check that the standard mark sits beside an assay office mark (leopard, anchor, rose or castle).
- Weigh the piece on a kitchen scale. Even a thin 9ct chain has noticeable heft for its size.
- When the marks are gone, post it. XRF confirms whether the alloy is 375 or something else.
When 9ct surprises you
A heavy 9ct curb chain or rope chain can hold more grams of gold than a small 18ct ring, because the weight matters as much as the purity. A 30 gram 9ct chain has 11.25 grams of pure gold. A 5 gram 18ct ring has 3.75 grams. The recovered yield difference is significant in favour of the chain. People are sometimes surprised that the "bigger but lower karat" piece outvalues the "smaller but higher karat" piece. Mass times purity is what matters.
Sending 9ct by post
9ct posts the same way as any other UK gold. WhatsApp 07763 741067 to start, request the prepaid Royal Mail Special Delivery envelope, send any 9ct items in. The XRF report shows the standard. Bank transfer follows acceptance. Decline is free return by tracked post. Your parcel is insured up to £2,500 via Royal Mail Special Delivery. The full method is on the sell gold by post page.
A close
375 is the British workhorse. It is not glamorous on a karat-vanity scale, but it is the karat that pays the most parcels through the door in the UK. A clean 9ct parcel, posted properly, is one of the most straightforward valuations a postal buyer does. If you have inherited a box of mixed gold, the 9ct in there is what you can count on for the bulk of the recovered yield.
Common questions
Is 9ct gold "real" gold?
Yes. It is 37.5% pure gold by weight, legally classed as gold under UK hallmarking.
Why is 9ct lighter in colour than 18ct?
There is less gold and more silver and copper or palladium in the alloy, so the yellow is paler.
Does 9ct tarnish?
The gold content does not tarnish. The copper and silver content can dull slightly on some 9ct yellows over decades. Polishing restores the colour.
Is 9ct stronger than 18ct?
Generally yes. The alloy is harder because of the higher base-metal content.
Can I sell a single broken 9ct chain?
Yes. Condition does not affect the recovered yield. Broken chains pay on the gold content.
Does 9ct white gold pay differently from 9ct yellow?
No. Same standard, same recovered gold per gram, same scrap figure at the same market level.
What does 9ct white gold look like under the rhodium?
A warm cream-white tone, slightly yellow. The rhodium plating gives it the bright cool white finish.
Is 9ct ever stamped "9k" instead of 375?
On US-imported pieces yes. The UK standard mark is 375. "9k" or "9kt" suggests foreign origin or an older UK stamp.