---
title: "How to test gold at home: which checks mean something, and which will damage it"
description: "The four checks worth running at a kitchen table, a plain verdict on the toothpaste, vinegar, ice and lighter tests, and why no home test gives a carat."
canonical: "https://assaypost.co.uk/guides/how-to-test-gold-at-home"
published: "2026-09-19"
modified: "2026-09-24"
language: "en-GB"
publisher: "Assaypost"
---

# How to test gold at home: which checks mean something, and which will damage it

Written at the Assaypost bench, checked before publication. Published 19 September 2026. Updated 24 September 2026.

**The short answer:** Four checks at a kitchen table can sort probably not gold from possibly gold, but none of them can tell you the carat. Hold a magnet to the body of the piece: gold alloys are not drawn to one, while a clasp that pulls is only its steel spring. Look at the wear points, where a different colour showing through means a coating over another metal. Read the marks under a magnifier: British gold is marked 375, 585, 750 or 916. And compare weight against size, because solid gold is far denser than brass. The Assay Offices' own guidance says precious metal content cannot be detected by sight or by touch. The toothpaste, vinegar, lemon, ice and float tests identify nothing, and the lighter and acid tests mark the piece.

## What a home test can settle, and what it cannot

A kitchen test has one job. It sorts a drawer into the things that are probably not gold and the things that might be, so that you stop spending attention on the first group and start asking proper questions about the second. That is worth doing, it costs nothing, and it is the whole of what a home test achieves.

What it cannot do is give you a carat. The hallmarking guidance published by the Assay Offices of Great Britain states that it is not possible to detect by sight or by touch the platinum, gold, palladium or silver content of an item. That is why hallmarking exists at all. A piece can pass every check below and still be 9ct, 18ct, gold-filled or heavily plated brass, and those four are very different things.

> **The decision a home check is for**
>
> You are not deciding what a piece is worth. You are deciding whether it is worth photographing and asking about. A piece that fails the magnet is settled and can go back in the drawer. A piece that passes everything is a piece nobody has identified yet.

## The four checks worth running

None of these needs anything you would have to buy, apart from a cheap magnifier if you have none, and none of them puts a chemical on the piece.

1. **A magnet**: Any fridge magnet will do, though a stronger one is better. Hold it against the body of the piece rather than the fastening. Gold, silver, platinum and palladium alloys are not attracted to a magnet. If a whole bangle, a whole ring or the length of a chain lifts towards it, that piece is not precious metal and you are finished with it. If nothing happens, you have learned that it is not steel, and nothing else.
2. **Wear points and colour break-through**: Look at the tips of chain links, the underside of a clasp, the edge of a ring shank, the high points of any raised decoration and the back of a pendant where it has rubbed on clothing. Coatings go from those places first. A yellow-pink or grey colour showing through means a different metal underneath, and one glimpse of it settles the question. Seeing no break-through means only that the piece is not worn through yet.
3. **The marks, read under magnification**: Rest the piece on something plain and pale, bring the light in from the side rather than straight on, and look with the strongest magnifier you have. A phone camera at its closest focus works. You are looking for a number, for a small walking lion on silver, and for a shaped shield with initials in it. Marks are often worn, half-struck or filled with polish, and a mark you cannot read is not the same thing as no mark.
4. **Weight against size**: Pick two pieces up, one in each hand, and compare. Solid carat gold is startlingly dense, and people who have never held any are surprised by it. A chain that feels lighter than it looks is hollow, plated or both. This is a comparison and not a measurement, and it works far better between two objects of similar size than on one object alone.

**What each result actually licences you to conclude**

| Check | If it passes | If it fails |
| --- | --- | --- |
| Magnet | Not steel. Could be gold, silver, brass, bronze, pewter, aluminium or lead | Not solid gold or silver, unless only the clasp or a spring pulled |
| Wear points | No coating has worn through where you looked. Says nothing about what is under an intact surface | A coating over a different metal. Decisive on its own |
| Marks | A claim about the metal, made by whoever struck it, which testing then confirms or contradicts | Nothing at all. Small items are exempt from marking and old items often lost theirs |
| Weight for size | Consistent with a dense metal. Gold, platinum, lead and tungsten are all dense | Hollow, plated, or a light alloy. Strong evidence, not proof |

Read that table across rather than down. Three of the four checks tell you far more when they fail than when they pass, which is true of nearly all cheap testing. The [sorting guide](https://assaypost.co.uk/guides/a-box-of-jewellery-you-cannot-identify) takes the same checks through a whole box rather than a single piece.

## Why a magnet passing proves nothing

The magnet is the most useful thing in the drawer and the most over-read. What it finds is iron, in practice steel, and it finds it very reliably. The Royal Mint explains the same effect in circulating coinage: the 5p and 10p changed from cupro-nickel to nickel-plated steel in 2011, and it is the iron in the steel core that makes them stick.

That is the limit of the information. Brass does not stick. Bronze does not stick. Pewter, aluminium, zinc alloys and most costume-jewellery castings do not stick. Neither does gold. A piece that sits quietly against a magnet has told you it is not made of steel, and a great many worthless things are not made of steel.

> **A clasp that pulls on a gold chain**
>
> Bolt rings, lobster clasps and spring-ring fastenings have a steel spring inside them, and that spring is steel on a 9ct chain exactly as it is on a plated one. If the magnet grabs the clasp and ignores the rest of the chain, that is the normal construction of a piece of gold jewellery and not a warning sign. Test the body, not the fastening.

The same goes for watch cases with a steel back on a gold front, spectacle frames with steel hinges, brooches with a steel pin and cufflinks with a steel swivel. Each of those is a mixed-material object where one small part is steel because steel is the right material for a spring. What the magnet is good for is the whole-piece pull, and a whole-piece pull is conclusive.

## Reading the marks, in British notation

A British hallmark is several small marks struck together, and the one people mean when they talk about carat is the fineness mark. It is a number in parts per thousand, not a letter and a k. The approved standards for gold under Schedule 2 of the Hallmarking Act 1973 are 375, 585, 750, 916.6, 990 and 999 parts per thousand. On jewellery, the first four are the ones you will meet.

**British fineness marks for gold and what each one is**

| Mark | Carat | Parts of gold per thousand |
| --- | --- | --- |
| 375 | 9ct | 375 |
| 585 | 14ct | 585 |
| 750 | 18ct | 750 |
| 916 | 22ct | 916.6 under the Act, struck as 916 |

A piece marked 10k or 14k was made for a market that uses that notation, most often the United States, and those pieces reach British drawers constantly through inheritance and travel. They are not British hallmarks and the number is a manufacturer's claim rather than an assay office's finding. The [hallmarks guide](https://assaypost.co.uk/guides/uk-hallmarks-and-fineness-guide) sets out what a full British mark contains and which foreign marks mean what.

A missing mark is what people most often misread. Articles below a certain weight are exempt from compulsory hallmarking, and for gold that weight is one gram, so a stud earring, a fine chain or a thin band may carry nothing and be perfectly good. The Assay Offices' guidance adds that any pre-1950 item may be described and sold as precious metal without a hallmark if the seller can prove it meets the minimum fineness and was made before 1950. A heavy unmarked piece, on the other hand, has not been identified yet, and only a test settles it.

## The folk tests, taken one at a time

Search for this subject and you will be shown the toothpaste, vinegar, lemon, ice, lighter, ceramic streak and float tests, usually as a numbered list with no verdict attached. Here is the verdict, method by method, with what each one actually measures.

**Seven household methods and what each is really measuring**

| Method | What it actually measures | Verdict |
| --- | --- | --- |
| Toothpaste rubbed on and wiped off | Abrasion. Toothpaste is a mild polish and nothing more | Measures nothing about the metal. On a plated piece it removes plating, which is the one result it can produce |
| Vinegar | Whether a dilute weak acid attacks the surface in a few minutes, which on most alloys it does not | Cannot separate gold from brass or bronze in the time anybody watches, and cannot separate 9ct from 22ct at all |
| Lemon juice | The same thing with citric acid instead of acetic | The same answer. It can also stain, and it attacks soft stones and old solder |
| The ice test | Thermal conductivity. Gold carries heat away quickly, so ice on gold melts faster than ice on plastic | Real physics, wrong conclusion. Silver, copper and aluminium all conduct heat as well or better, so it separates metal from non-metal and nothing else |
| The lighter test | How the surface behaves when heated, which is a question nobody needs answered | Destructive. It discolours the surface, softens the metal, opens solder joints, ruins patina and can crack or burn a stone |
| The ceramic streak test | The colour of the trace left when metal is dragged across unglazed ceramic | Does separate gold from iron pyrite for a prospector. On jewellery it marks the piece, and a gilt surface leaves a gold streak too |
| The float test | Whether the object is denser than water | Brass, steel, lead, pewter and glass all sink. It excludes almost nothing |

Two of those deserve more than a line in a table. The lighter test does real harm, because heat does not stop at the surface. It softens the metal, takes the temper out of a spring and opens the solder at a link or a setting. It will craze or burn pearls, amber, coral, opal, turquoise and emerald without warning. A piece worth keeping as jewellery can stop being worth keeping in ten seconds.

The acid test is the other. It is a long-established trade method, not a home one. The Goldsmiths' Company Assay Office describes touchstone testing as lightly rubbing the article onto a stone of basanite. Every other traditional method it lists needs a physical sample taken from the article by scraping or drawing. Testing acids are corrosive, and applied to the piece rather than to a streak they leave a permanent dull mark. No procedure for either is given here, and it is wise to be wary of any page that gives one.

> **Two methods that mark or destroy**
>
> The lighter test and the acid test both change the piece. Neither can be undone, both lower what an object is worth if it turns out to be worth more than its metal, and neither of them would have told you a carat anyway.

## Carat is the number, and no kitchen test reaches it

Suppose every check goes your way. The magnet ignores the piece, the wear points are clean, there is a mark you cannot quite read, and it feels heavy for its size. You now know you are holding something that might be gold. You do not know whether it is 9ct or 22ct, and 22ct holds well over twice as much gold as 9ct in the same weight of metal.

That is why the home tests stop where they do. Establishing a fineness needs an instrument or a laboratory, and more than one method, because each has a gap. The Goldsmiths' Company Assay Office uses non-destructive X-ray fluorescence alongside touchstone work, cupellation, titration and, for platinum and palladium, ICP analysis. It notes that on occasion the surface layer has to be removed to find out what the alloy underneath is. The [XRF guide](https://assaypost.co.uk/guides/xrf-testing-capabilities-and-limits) explains where surface reading goes wrong, and the [testing page](https://assaypost.co.uk/testing-and-xrf) sets out the methods Assaypost uses.

The most useful thing you can do at home is not a better test but a better photograph. A sharp picture of a mark, a worn link tip and the whole piece beside a ruler answers more than any of the seven methods above. It lets a person who reads hallmarks tell you what you are holding before you post anything. That is what the [photo route](https://assaypost.co.uk/photo-estimate) is for, and the [sell gold page](https://assaypost.co.uk/sell-gold) explains what happens after it.

## Seller risks and exceptions

- Testing a piece that should not be tested. A signed brooch, a pocket watch or a piece of antique silver can be worth considerably more intact than as metal, and a scratch, a burn or an acid mark on it is money gone. Identify first, test later, and see [what to keep back](https://assaypost.co.uk/guides/what-to-have-looked-at-before-you-sell).
- Reading a pass as a result. Three of the four checks only tell you something when they fail. A piece that passes all four has not been identified; it has only survived elimination.
- Trusting a number stamped on a piece. A fineness mark on an unhallmarked item is a claim by whoever struck it. Gold-filled stock is stamped with a real carat and a fraction, and thickly gilded pieces are stamped with plating codes that look like fineness marks.
- Cleaning or polishing before you photograph. Polishing takes metal off the highest points of a piece, which is exactly where the hallmark is. See [whether to clean before you sell](https://assaypost.co.uk/guides/cleaning-and-polishing-before-you-sell).
- Assuming a magnet-free clasp means a gold chain. Plated brass does not stick to a magnet either, which is why the wear points and the weight matter alongside it.
- Forcing a watch case back to look for marks. Cases are fitted, snapped or screwed, and a slipped knife marks the case and the movement. A jeweller opens one in seconds.

## When not to test it yourself at all

> **Put the piece down and ask first**
>
> Anything with a maker's name on it. Any watch that runs. Any coin, because a coin's surface is part of what it is worth and a test mark is permanent. Anything set with stones, because acids, heat and abrasives all attack the stones before they attack the metal. Anything old enough that the marks are worn shallow, because a rub or a scratch takes the last of them off.

For those pieces the sensible first move costs nothing and changes nothing. Photograph the marks and the piece and ask what it appears to be, or take it to a valuer or a saleroom and ask for an opinion. The guide to [valuation, appraisal or offer](https://assaypost.co.uk/guides/valuation-appraisal-or-offer) sets out which of those you actually need and which you do not, and [what we buy](https://assaypost.co.uk/what-we-buy) says plainly which materials are taken here and which are not.

## Questions sellers ask

### Does the toothpaste test work on gold?

No. Toothpaste is a mild abrasive, so all it does is polish the surface. It cannot distinguish gold from brass and it cannot tell you a carat. On a plated piece the one thing it can achieve is taking some of the plating off.

### My gold has no hallmark. Does that mean it is not gold?

Not on its own. Gold articles under one gram are exempt from compulsory hallmarking, so small studs, thin chains and light bands often carry nothing. Pre-1950 items can also be sold as precious metal without a mark where the seller can prove the fineness and the date. A heavy unmarked piece is unidentified, and only a test settles it.

### Why does my gold chain stick to a magnet at the clasp?

Because the clasp contains a steel spring, and it does on real gold chains as much as on plated ones. Hold the magnet to the body of the chain instead. A pull along the links themselves means the chain is not gold; a pull only at the fastening means nothing at all.

### Can I tell 9ct from 18ct at home?

No. Colour is not reliable, because alloys are mixed to hit a colour, and weight in the hand cannot separate them either. The fineness mark is the only thing at home that speaks to carat, and a mark is a claim until it is tested. That is the gap between a home check and an assessment.

### Is the acid test safe to do myself?

It is not a home method. Touchstone testing works by rubbing metal off the article onto a stone, testing acids are corrosive, and used on the piece itself they leave a permanent mark. No procedure for it is published here.

### What should I do instead of testing it?

Run the magnet over it, look at the wear points, photograph any marks with the light coming from the side, and [send the pictures](https://assaypost.co.uk/photo-estimate) for an opinion on what the pieces appear to be. That costs nothing, commits you to nothing and answers more than any kitchen method.

## Sources

1. [GOV.UK — Hallmarking is the law: guidance summary (British Hallmarking Council and the Assay Offices of Great Britain)](https://www.gov.uk/government/publications/hallmarking-guidance-notes/hallmarking-is-the-law-guidance-summary) (accessed 19 September 2026)
2. [Assay Offices of Great Britain — Hallmarking guidance notes: practical guidance in relation to the Hallmarking Act 1973](https://assets.publishing.service.gov.uk/media/63a333b9d3bf7f37654767e0/hallmarking-guidance-notes.pdf) (accessed 21 September 2026)
3. [legislation.gov.uk — Hallmarking Act 1973, Schedule 2: approved standards of fineness](https://www.legislation.gov.uk/ukpga/1973/43/schedule/2) (accessed 21 September 2026)
4. [The Goldsmiths' Company Assay Office — Our hallmarking methods: XRF, touchstone, cupellation, titration and ICP](https://www.assayofficelondon.co.uk/hallmarking/our-hallmarking-methods) (accessed 21 September 2026)
5. [The Royal Mint — Why are some UK coins magnetic?](https://www.royalmint.com/stories/collect/why-are-some-uk-coins-magnetic/) (accessed 21 September 2026)

## Related

- [A box of jewellery you cannot identify: where to start](https://assaypost.co.uk/guides/a-box-of-jewellery-you-cannot-identify)
- [Reading UK hallmarks on gold, silver, platinum and palladium](https://assaypost.co.uk/guides/uk-hallmarks-and-fineness-guide)
- [XRF testing: what it measures, what it cannot prove, and how a reading becomes a fineness](https://assaypost.co.uk/guides/xrf-testing-capabilities-and-limits)
- [Gold plated, rolled gold, gold-filled and vermeil compared](https://assaypost.co.uk/guides/plated-rolled-gold-filled-and-vermeil)
- [Should you clean or polish gold and silver before you sell it?](https://assaypost.co.uk/guides/cleaning-and-polishing-before-you-sell)
- [Send photos first](https://assaypost.co.uk/photo-estimate)
- [Testing and XRF](https://assaypost.co.uk/testing-and-xrf)

## Start with photographs

- [Send a photo on WhatsApp](https://wa.me/447369296063?text=Hello.%20I've%20been%20reading%20your%20guides%20and%20I've%20got%20some%20pieces%20I%20can't%20identify.%20Sending%20photos%20now.)
- [Request a prepaid label](https://assaypost.co.uk/postal-pack)
- Telephone [07369 296063](tel:07369296063), 6am to 10pm, seven days a week