Diamond & Jewellery Guides

What we would tell you across the counter, written down. No hedging, no upsell — the numbers, the trade-offs and the answer.

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The four questions we are asked most

Is a laboratory-grown diamond a real diamond?

It is a diamond, and UK terminology rules ask that it always be called a laboratory-grown one rather than simply a diamond — the qualifier is the point. ISO 18323 defines it as having essentially the same chemical composition, crystal structure and physical properties as a mined stone: the same crystalline carbon, the same 10 on the Mohs scale. GIA grades both against the same four Cs. What differs is how it was formed, and what that does to the price.

What is the average ring size in the UK?

Around a UK size L for women and a UK size T for men, though both spread widely — most women fall between G and T. Those are starting points for a guess rather than a substitute for measuring, and our ring size guide sets out how to measure properly.

Does every piece of gold jewellery have to be hallmarked in the UK?

Any gold article over one gram sold in the UK must carry a British hallmark, and the thresholds are 7.78g for silver, 0.5g for platinum and 1g for palladium. We hallmark at the London Assay Office, whose counter is on Greville Street in Hatton Garden — a few minutes from the bench the piece was made on.

How long does a bespoke ring take to make?

Longer than most people expect, because casting, setting, finishing and hallmarking at the London Assay Office are each a real step. We give you a date when we quote rather than a rule of thumb, since it depends on the piece. If you are working to a deadline, say so at the start.