Gold jewellery bought on a trip raises two practical questions that have nothing to do with whether buying it is a good idea, which is not something this site will judge. The first is what the stamp inside it actually means, given that it was struck under another country’s rules. The second is what the customs authority at home expects when it comes through the airport. Both have clear answers, and both are easier to deal with before the trip than after it.
A stamp is a claim made under somebody’s rules
A purity mark such as 750, 916 or 21K says what fraction of the metal is gold. Who made that claim, and who checked it, depends entirely on where it was struck. In the United Kingdom an independent assay office tests the metal and strikes the hallmark. In the United States there is no government assay at all: a maker marks its own metal and is answerable under federal law if the mark is wrong, within tolerances set out in 15 U.S.C. § 295. India runs a mandatory hallmarking scheme through the Bureau of Indian Standards, in which each hallmarked piece carries a six-character HUID code alongside its purity mark. Other countries run other systems.
So the same number can carry very different weight. A UK hallmark and a maker’s own stamp may both say 750, but only one of them records that an independent laboratory tested the piece. Neither is a guarantee about any individual article, and neither says anything about its value. The gold purity by country page sets out the standards several jurisdictions recognise, and the karat converter turns any karat or fineness into the other.
Karat and fineness are the same fact written two ways
Some markets describe gold in karats and some in parts per thousand. Karat is a fraction out of 24, so 18K is 18/24 = 750 parts per thousand exactly, 21K is 875 and 22K is 916.7. A piece sold as 22K and stamped 916 is making the same claim twice. Where a piece is described one way and stamped another, it is the stamp and the receipt that record what was actually claimed, so it is worth reading the stamp rather than the shop sign.
A foreign mark is not a UK hallmark
For anyone bringing gold back to Britain, one distinction matters. Under the Hallmarking Act 1973, articles described as gold when they are sold in the course of business in the UK must, unless exempt, carry an approved hallmark. A foreign maker’s own stamp is not one. One mark that is recognised is the Common Control Mark of the International Hallmarking Convention, which is applied by the assay offices of member states and is recognised by the UK; the Convention marks page lists the finenesses it covers. This is a rule about dealing, not about owning: nothing stops a person wearing jewellery marked abroad. It becomes relevant if the piece is later offered for sale through a business in the UK, which may need it assayed first. Very light articles are exempt; the exemption weights page gives the thresholds.
What to measure and keep at the time
The two facts that fix how much gold a piece contains are its weight and its fineness. Both are easy to record at the time of purchase and harder to establish later without a scale. A receipt that states the weight in grams, the purity and the price of each item records all three, and it is also the kind of evidence of value that a customs declaration draws on.
From weight and fineness, the gold content follows by arithmetic. The gold calculator gives the melt value of any weight and karat at the live price. That is a measurement of the metal only: it is not what the piece cost, and it is not what anyone would pay for it. Jewellery is priced with making charges and margins on top of the metal, and a buyer later pays the metal less their margin. The guide to why melt value is not worth explains the gap.
Customs: three examples
Every country sets its own allowance for goods brought home, and some treat jewellery or gold separately. The rules below were read from each government’s own pages on 9 October 2026. They change, and they come with conditions this summary leaves out, so the authority’s current page is the one to rely on before travelling.
United Kingdom
Arriving in Great Britain from outside the UK, GOV.UK gives an allowance for “other goods” worth up to £390, or up to £270 when arriving by private plane or boat. Going over it has a sharp edge: GOV.UK states that tax and duty are then paid on the total value of the goods, not just the value above the allowance. Goods over the allowance must be declared, which can be done online up to five days before arrival.
United States
US Customs and Border Protection requires that anything a traveller brings back which they did not have when they left the United States be declared. Returning residents have a personal exemption, typically $800, usable once every 31 days, with a higher figure in some circumstances. CBP lists jewellery among personal effects. Declaring is separate from paying duty: an item can be within the exemption and still need declaring.
India
India replaced its Baggage Rules on 2 February 2026. According to the customs FAQ on the 2026 rules, a resident or a tourist of Indian origin who has been living abroad for more than one year may bring jewellery duty-free up to 40 grams for a female passenger and 20 grams for any other passenger. The 2026 rules set these allowances by weight alone, removing the rupee value caps that applied under the 2016 rules. Used personal jewellery reasonably required for the journey is allowed duty-free; other bona fide personal jewellery is allowed on payment of duty. Gold in other forms falls under separate conditions and import policy. For jewellery taken out of India and brought back, the FAQ describes an export certificate that can be obtained before leaving, so that the item’s earlier ownership can be shown on return.
The short version
- The stamp says what was claimed, under the rules of the place it was struck.
- Weight in grams and fineness are the two facts worth recording on the receipt.
- Melt value, retail price and what a buyer pays are three different numbers.
- Customs allowances are set per country and change; read the current rule before the trip.