When is 925 not 925? That is the question...

It's a legal requirement in the UK that all sterling silver jewellery that weighs over 7.78g must be submitted to one of the official assay offices for testing and hallmarking. Whilst this is expensive and can cause an annoying delay, it provides very valuable consumer protection and guarantees that what you think you are buying is what you are actually getting.

Under 7.78g*

, there is no requirement to hallmark. Whilst I would like to do so, it would add significantly to the cost of the jewellery, so I have decided at present not to do so routinely. Of course, if you would like something hallmarked, then please let me know. I am registered at Birmingham Assay Office.

You will see many pieces bearing a 925 stamp, which is intended to denote that the piece is of sterling silver quality. Unfortunately, these stamps are on open sale and can be bought quickly and cheaply on the internet from any jewellery supplier or even Amazon. Whilst it is illegal to falsely describe a piece of jewellery as sterling when it isn't, in practice it happens all the time. Many pieces on Etsy bear the 925 stamp without a scrap of silver in them.

Most small makers (like me) are proud of what they make and their jewellery is honestly described. However, there are a lot out there who buy cheap from China and sell on as "handmade". This "silver" may contain nickel, cadmium, and zinc, amongst other things. Not what you want against your skin.

So how do you tell if you have real silver or not?

The quickest and easiest way is with a magnet. Real silver is not magnetic.

This is a costume "silver"chain. It is silver plated, but the core is a steel alloy. There is no need to test it any further. This is not a sterling silver chain.

The magnet test is not definitive. Brass and many other alloys are also not magnetic, so would pass the first test. Now you look carefully for any wear- if you can see any hint of where the coating has rubbed off you will be able to see the underlying metal. Again, this means that the piece is not solid sterling.

If it's passed these two quick and easy tests, then it may be silver or it may not. I use an acid test as my final check. This is a potent mix of Nitric Acid and Potassium Dichromate. It's easy to buy online and very accurate. It will turn a range of colours depending on the composition of your metal.

This is a white metal chain I was given as "silver". It passed the first two tests and the colour, weight and "feel" were all indicative of silver.

It's a very pretty chain with small balls every couple of inches, and I'd love to reuse it.

I tried the acid test on it. I scratched the ball nearest to the chain where it isn't really going to show. This is to expose the core metal and avoid a false reading from any plating.

The big red dot is the same acid on a piece of scrap sterling silver, and that is the colour I was looking to see appear on the ball of the chain (5 links down from the catch). As you can see, there is no reaction whatsoever.

Whatever this chain is, it isn't sterling silver, in fact it's not testing as any grade of silver at all.

So in conclusion - I have no idea what this chain is made of without commissioning a laboratory or xray analysis. What I do know is that it is not silver and it will therefore go into the box with the rest of my costume chains.

*7.78g is a strange choice of threshold but there is a reason! Traditionally, precious metals are measured in "pennyweights" (dwt) and a few dealers do still use it. 7.78g is just a metric conversion of 5 pennyweights.  The original pennyweight was the weight of an English silver penny during the reign of Edward I (1272 to 1307).