How to test silver at home: the hallmark, magnet, ice and acid tests

Start with the hallmark: the fastest reliable test

Most UK silver over 7.78g must carry a UK Assay Office hallmark. A legible stamp tells you almost everything you need to know:

• 925 or the lion passant: sterling silver (92.5% pure).
• 958: Britannia silver (95.8% pure), softer, higher fineness, less common.
• 800: continental European silver (80%). Common in German and Italian pieces.
• EPNS: Electro-Plated Nickel Silver. Not silver. A thin silver layer over nickel silver, an alloy of copper, nickel and zinc with no silver in it.
• A1 or "silver on copper": silver-plated. Not solid silver.

For the fast way to decode a mark, see how to read a hallmark in 60 seconds, the layout logic is the same on silver: standard, town, date letter, maker.

The magnet test: a negative test only

Silver is not magnetic. Hold a strong neodymium magnet against the piece: if it sticks, the core is a ferrous metal and it is definitely not solid silver. That is genuinely useful.

The catch: copper, brass, aluminium and lead are also non-magnetic. So a piece passing the magnet test has not proved it is silver. It has only proved it is not iron or steel. Treat it as a screen that eliminates the obvious fakes.

The ice test: a genuinely good screen

Silver has the highest thermal conductivity of any metal. Put an ice cube on a silver coin at room temperature and it starts to melt visibly faster than the same cube on a brass, nickel-silver or steel piece of the same size. Copper conducts heat almost as well as silver, so the ice test cannot tell silver from copper. It is not a lab measurement, but the difference against brass or plate on a flat sterling piece is obvious to the naked eye within about 15 seconds.

The test works best on flat objects, coins, ingots, spoons. It works poorly on hollow items and plated items (the surface conducts, the core does not). Use it as a confirmatory screen alongside the hallmark reading.

The acid test: risky, approximate, damaging

Silver acid test kits are sold cheaply. They work by applying a drop of nitric-acid-based reagent to a small scratch on the piece; the colour of the resulting mark indicates approximate fineness. They can usually tell 925 from 800 from plate.

The downsides are real: you have to scratch the item to reveal fresh metal, the acid burns skin and fabric, the reagents degrade over time, and the result is a colour judgement, not a number. For a chain you plan to keep, the damage may cost more than the certainty is worth. For a piece you plan to sell for scrap, XRF is free at our end and does not scratch anything.

What XRF settles

X-ray fluorescence reads the elemental composition of a metal in seconds and reports percentages: silver, copper, zinc, gold, lead. It does not damage the piece. It sees through moderate surface tarnish. It will distinguish sterling (925), Britannia (958) and continental (800). Plate needs more than one reading, taken with the weight and the wear points, because a plated surface can read as silver.

We test every parcel by in-house XRF as part of our standard process. There is no charge and no obligation to sell. See sell sterling silver for how we quote and pay. If you want the reading without selling anything, paid XRF metal testing works by post, with no obligation to sell.

A short decision tree

1. Read the hallmark first. If it says 925, 958 or 800 with an Assay Office mark, you are almost certainly holding silver.
2. If no legible mark, run the magnet. If it sticks, stop, not silver.
3. If no mark and non-magnetic, run the ice test. Fast heat transfer is a strong indicator.
4. Still unsure? Send it to us for XRF. Free tracked return if you decline.

Patterns worth knowing

• Victorian teaspoons with a lion passant and a clear town mark: sterling.
• Bright, uniformly-shiny cutlery sets marked "A1" or "EPNS", plated, not solid.
• Continental brooches marked 800 with a maker’s cypher, genuine 80% silver.
• Modern chain stamped 925 by the maker: usually sterling, though only a hallmark or a test confirms it.
• Bullion coins (Maple Leafs, Britannias from 2013): 999 silver, with weight and stamp matching published mint specifications.

When to skip home testing entirely

If the piece is antique, signed by a known maker, or looks like it might be Georgian or earlier, do not test it yourself. Acid and scratch tests damage marks that carry the value. Send us photographs first; if it belongs at specialist auction rather than at our bench, we will tell you.