British Gold Exchange · Est. 1985 · London

Seller guide

How to prove your gold is genuine, and what to do if you are not sure

You do not need to be certain before sending us anything. Understanding how gold is identified will give you confidence in the process.

Why British Gold Exchange

40+

Years in the precious metals business

£0

Cost to request your free insured postal pack

24h

Maximum time to receive your firm, itemised offer

100%

Of items returned free if you decline

Ready to get a valuation?

The short answer

UK hallmarks are the most reliable proof. For everything else, XRF testing is definitive

In the United Kingdom, any gold item above 1 gram sold as gold must by law carry an assay office hallmark. The hallmark is stamped by one of the four UK assay offices (London, Birmingham, Sheffield or Edinburgh) and consists of the maker's mark, the purity mark (a number like 375, 585 or 750) and the assay office symbol. If your piece carries a hallmark, its purity is legally guaranteed.

Many items, particularly foreign pieces, older jewellery and inherited items, may not carry a UK hallmark but are still genuine gold. XRF (X-ray fluorescence) analysis is a professional, non-destructive test that confirms purity in these cases, and it takes seconds. Every item we receive is XRF-tested regardless of whether it has a hallmark.

If you are uncertain whether something is gold, send it anyway. We do not buy gold-plated items. If a piece turns out to be gold-plated, gold-filled or base metal, we will explain this clearly in writing and return it at no cost. You will never receive a lower offer than the metal actually warrants.

What affects it

Testing methods and what each tells you

UK hallmarkThe most reliable method. Look for a number (375, 585, 750, 916) stamped into the metal, usually on the inside of a ring or the clasp of a necklace. This is the fineness: the gold purity in parts per thousand.
XRF analysisA professional, non-destructive test using X-ray fluorescence. It gives a reading in seconds, and we use it on every item we receive.
Acid testA small scratch is made and a drop of nitric acid applied. Genuine gold resists the acid; base metals react. It is reasonably accurate for sorting but damages the piece, so we do not use it.
Magnet testGold is not magnetic. If a piece is strongly attracted to a magnet, it is not solid gold. However, many non-gold metals are also non-magnetic, so a negative result is not confirmation.
Density testPure gold is very dense (19.3 g/cm³). Weighing a piece in air and in water allows calculation of density. It is accurate for solid pieces but impractical for hollow jewellery.
Skin discolourationSome people note that fake gold leaves a green or black mark on skin. This is caused by copper or other base metals reacting with skin chemistry. Genuine gold does not react, but this is not a reliable test.
No hallmarkThe absence of a UK hallmark does not mean a piece is not gold. Foreign gold often uses different marking systems, and older pieces pre-date compulsory hallmarking. XRF resolves this definitively.

How it works

From first contact to payment

01

Request your free pack

We send you a free pack with a prepaid, tracked Royal Mail Special Delivery label, dispatched the next working day. There is no cost and no commitment.

02

Send your items

Pack your items in the packaging we supply and hand them in at a Post Office. They are insured up to £2,500 from that moment until they reach us.

03

Receive your offer

Every piece is XRF-tested on arrival to confirm exact purity. Your offer is based on this tested reading rather than an estimate.

04

Get paid

Accept before 3pm on a working day for a same-day bank transfer. Decline and we return every item free of charge.

Common questions

Questions we hear most

What if I think I have gold but I am not certain?

Send it. We test everything with XRF regardless of what you think it is. If it is not gold, we return it and tell you what it is. There is no charge for an assessment.

My gold does not have a hallmark. Will you still buy it?

Yes. We buy unmarked gold regularly, particularly foreign pieces, antique items and dental gold. The XRF test confirms purity independently of any stamp.

Can plated items have any value?

We do not buy gold-plated items. They have no significant gold value, as the coating is usually less than 0.05% of the weight. If a plated item has collector value (vintage, designer), that is a separate matter from its gold content, and we will return it to you.

What is 'gold filled' or 'gold overlay'?

Gold-filled items have a thicker layer of gold mechanically bonded to a base metal core: more than plating, but less than solid gold. The gold layer is typically 5% of the total weight. We assess these on a case-by-case basis.

Will the XRF test damage my items?

No. XRF is entirely non-destructive. The piece is placed in the analyser, a reading is taken in seconds, and the piece is removed unchanged. It is safe for all types of jewellery including pieces with stones.

Get started

Not sure what you have? We will find out, free of charge

Send your items in our free insured pack and receive an XRF-verified offer within 24 hours. If it is not gold, we return it at no cost.

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