Start with the visual tells
A charity shop manager has seen more gold pass over the counter than most jewellers have in a week. The eye learns the cues quickly. Real gold has a softness to its colour that base metal struggles to copy. Yellow gold has a warm, slightly buttery tone. Rose gold has a pink cast from the copper in the alloy. White gold has a cool grey-silver tone with a slight yellow undertone in the alloy beneath the rhodium plating.
The most useful visual tell is wear at high-friction points. Look at the inside of a ring shank, the catch of a chain, the back of a brooch, the pin of an earring. On real gold these points wear evenly and stay the same colour as the rest of the piece. On plated base metal, the same points wear through to a different colour underneath: usually a dull grey or a coppery pink. A chain with a coppery flash where the catch rubs the shoulder is almost always plate.
A second useful tell is the green or black skin reaction sometimes reported by donors. Gold above about 14 carat very rarely causes this. The reaction is from copper, nickel or zinc in low-carat alloys or in base-metal plating. It is not a definitive negative for real gold (9-carat with high copper content can cause it), but combined with weight that feels light for the size, it is a strong hint towards plate.
Hallmarks: the first sorting step
British gold is hallmarked. A genuine UK hallmark includes the carat fineness (375 for 9-carat, 585 for 14-carat, 750 for 18-carat, 916 for 22-carat, 999 for 24-carat), a town mark, a date letter, and a maker's mark. The marks are small but crisp under a 10x loupe. A piece with a complete, crisp set of marks is almost certainly the carat it claims, although hallmark fraud does occasionally exist.
A piece marked "14k" or "14kt" without surrounding British marks is most likely European, American, or Middle Eastern. These foreign carat marks are not subject to UK assay-office testing. They are often accurate, but they are not the legal guarantee a British hallmark is. Treat them as a strong hint, not a certainty.
A piece marked GP, GF, GE, RGP, GEP, or 1/20 12K is plated or rolled gold. GP is gold plate. GF is gold filled. GE is gold electroplate. RGP is rolled gold plate. 1/20 12K is a thin layer of 12-carat gold over a base metal, totalling one-twentieth of the piece by weight. None of these have meaningful precious-metal recovery value, and they should be priced as costume on the shop floor.
The magnet test, and why it is not definitive
A neodymium magnet costs a few pounds and is a useful first-pass filter. Hold the magnet against the piece. If the piece is strongly attracted, it contains iron or steel and is not gold. Real gold is not magnetic.
The trap is that the reverse is not true. Many fakes are deliberately made from non-magnetic base metals: brass, bronze, copper, zinc alloys. A non-magnetic result tells you the piece could be gold, not that it is. The magnet test rules out one common fake material (cheap steel chains plated to look like gold) and rules in nothing.
Use the magnet as a quick first sort on a busy donation table. Pull anything that strongly attracts and set it aside as definitely-not-gold. The rest still needs a closer look.
Density and water displacement: last resort only
Gold is unusually dense: 19.3 grams per cubic centimetre for pure gold, lower for alloyed carats (about 15.5 for 18-carat yellow, about 12.5 for 14-carat, about 11.0 for 9-carat). Most base metals used in fakes sit between 8 and 9 grams per cubic centimetre. In principle a charity shop can measure density by weighing the piece dry and then weighing it suspended in water, using the difference to calculate the volume displaced.
In practice this is a last-resort test. The arithmetic is fiddly, the result is sensitive to small measurement errors, and pieces with hollow sections (chains, hollow rings, hollow earrings) give misleading readings because the trapped air reduces apparent density. A density test that says "real gold" on a hollow chain proves nothing. A density test that says "definitely not gold" on a solid piece is more useful, but XRF will say the same thing in two seconds and tell you the exact alloy.
Do not run a density test on the donation table. It is slow, the bowl gets in the way, and the donor is watching. If a piece looks worth testing, post it.
The acid test: do not
Acid testing has been a standard jewellery-trade tool for decades. The piece is scratched on a touchstone and a drop of nitric acid is applied to the scratch. Real gold of the claimed carat does not react. Lower-carat gold or base metal reacts visibly.
A charity shop should not do this. The reasons are practical and ethical.
- The test is destructive. The scratch is small but it is permanent, and it removes a few milligrams of metal. On a heavy bangle the damage is invisible, but on a thin Edwardian chain or a delicate ring with engraved detail it can reduce the resale value of a real piece.
- Acid is hazardous. Nitric acid burns skin and damages eyes, and the fumes irritate airways. A donation table in a public-facing shop is not a place to keep concentrated acid.
- The reading is interpretive, not numerical. A trained eye reads the rate and colour of the reaction. An untrained eye can misread a real 9-carat piece as plate, or miss a clever fake.
- XRF gives a numerical reading of the exact alloy composition in two seconds, non-destructively, and the reading is on the report the charity sees.
There is no situation in which a charity shop benefits from running its own acid test. Post the piece. If it is real, XRF will confirm it. If it is not, the parcel comes back at GoldPaid's cost.
Fool's gold and other look-alikes
Fool's gold is iron pyrite, a yellow-brassy mineral that occasionally turns up in donations of curios, geology samples, or grandfather's tin of pebbles. It is hard, crystalline, brittle, and forms cube or pyrite-octahedron shapes when natural. Real gold is soft, malleable, and forms no crystals. A fingernail will not scratch pyrite. A fingernail will scratch pure gold and mark soft 22-carat. Pyrite is non-magnetic, so the magnet test does not catch it, but the visual difference is unmistakable once you have seen both.
Other common look-alikes are: brass (warmer tone, lighter weight, develops a dull patina), gilded base metal (a thin gold layer over brass or steel, wears through quickly at edges), and modern fashion-jewellery plate (very thin layer, often over a zinc-alloy casting, often non-magnetic). None of these have recoverable gold content. All of them are correctly priced as costume on the shop floor.
Why XRF is the only certain answer
XRF stands for X-ray fluorescence. A handheld XRF analyser fires a low-energy X-ray beam at the piece. The atoms in the alloy fluoresce, emitting their own characteristic energies, and the analyser reads the spectrum. Within two seconds it gives a numerical breakdown of the alloy: percentage gold, percentage silver, percentage copper, percentage zinc, percentage palladium, and any trace elements.
The reading is non-destructive. No scratch, no acid, no heat, no mark on the piece. The reading is numerical, not interpretive: the alloy composition is either above or below the carat threshold and the report says so in plain numbers. The reading is reproducible: a second XRF read on the same piece gives the same numbers, so a charity finance team or auditor can verify any valuation. XRF testing explained covers the method in more detail.
Indicative figures move with the market; the firm offer is set only after XRF assay confirms purity and weight of the specific items sent. Royal Mail Special Delivery cover is up to £2,500, higher available on request before posting.
The WhatsApp photo step
Before any parcel is sent, a shop manager can send a photo on WhatsApp to 07375 071158 with the piece next to a coin for scale and the hallmark in focus where one is visible. The team will give an indicative response within the hour during working hours: post, or do not post. This filters out plated pieces before they hit the postage queue and saves shop time.
A useful photo shows: the piece flat on a plain background (a sheet of A4 paper is ideal), a coin for scale, the hallmark area in a second close-up, and any wear-through points visible. A blurry phone photo at arm's length is enough to start the conversation. A loupe close-up of the hallmark is the gold standard but is rarely needed.
The decline path
If a piece is posted, XRF-tested, and turns out to be plated or base-metal, the parcel is returned to the shop tracked and insured at GoldPaid's cost. Free insured return of any item the charity chooses not to sell. There is no fee for a returned parcel and no restocking charge. The shop can then price the piece as costume on the shop floor.
If a piece is real gold and the offer is accepted, payment is by Faster Payment direct to the charity's registered bank account, where the offer is accepted before 3pm UK time on a working day. A trustee-friendly PDF summary is generated automatically and emailed to the charity's head-office contact.
Common questions
A chain has no hallmark but the seller claimed it was gold. Should I post it?
Take a photo of the chain laid flat with a coin for scale, plus a close-up of the catch and the bale where wear shows. Send on WhatsApp to 07375 071158. Unhallmarked chains are sometimes foreign gold, sometimes plate. The photo gives an indicative answer before you post.
The piece is marked "925". Is it gold?
No. 925 is the sterling silver fineness mark. A piece marked 925 is sterling silver, sometimes with a gold-coloured plate over the top (vermeil). Vermeil is correctly priced as costume on the shop floor for charity purposes; the silver content underneath has some value but is rarely worth posting on its own.
A bangle attracts the magnet weakly. Is it gold?
No. Real gold is not magnetic at all. A weak attraction means the bangle has a steel core or a magnetic alloy underneath. It is not gold. Price as costume on the shop floor.
Can a charity shop buy a cheap XRF for the back room?
Handheld XRF analysers start in the low five figures and require radiation-handling registration with the Health and Safety Executive plus annual calibration. They are not a practical purchase for a charity retail estate. The free WhatsApp photo step plus a posted parcel is the proportionate route.
What is the cheapest test we can keep on the donation table?
A 10x loupe (under £10) and a neodymium magnet (under £5). The loupe lets a manager read a hallmark clearly. The magnet rules out steel-cored fakes. Together they cover the majority of first-pass decisions. The rest is the WhatsApp photo.
A donor brought in something they say is 24-carat. Is that realistic?
24-carat is 999 fineness, pure gold. It is unusual in British jewellery because it is too soft to hold a setting or take wear, but it is common in investment bars, sovereigns, and some Middle Eastern, South Asian and Far Eastern jewellery. A 24-carat piece will have a soft, deep yellow colour and feel heavier than expected. Worth posting in every case.