The short answer
An AI app can give you a number for your jewellery, and sometimes a surprisingly good one. What it cannot give you is a valuation. A photograph can suggest what a piece might be. Only someone who has held it, tested it and measured it can tell you what it is, and put their name to what it’s worth.
What happens when you ask AI to value a ring
Take a photograph of a diamond ring, upload it to an AI app and ask what it’s worth.
Within seconds you may be told it’s an 18ct white gold diamond solitaire. You’ll be given an estimate of the diamond’s size and quality, shown a few similar rings found online, and offered a replacement value of, say, £8,500.
It’s impressive, and it’s getting better every day. It’s also very easy to believe, because the answer arrives sounding completely sure of itself. AI doesn’t sound any less confident when it’s wrong.
What a photograph can’t tell you
Before I’d accept that £8,500, there’s a great deal I’d want to know. None of it can be answered from a picture.
- Is it really a diamond? Several stones look like diamond in a photograph. Some of them are worth a fraction of the price.
- Is it natural or laboratory-grown? The two can look identical, even to an experienced eye. Telling them apart takes testing, and the difference in value is enormous.
- How much does it weigh? A photograph can only guess at size. A stone’s weight is measured on a scale, or carefully calculated from real measurements.
- What colour and clarity is it? Colour has to be judged in the right light, and clarity under magnification. A phone camera flatters both.
- Has it been treated? Many gemstones are treated to improve their colour or clarity, which affects their value, and the evidence is usually invisible in a photograph.
- What is the mount made of? Metal has to be tested. Hallmarks have to be found, read and checked against the piece they’re on.
- What condition is it in? Worn claws, old repairs and a thinning shank all matter, and a flattering photograph hides them.
Every one of those answers changes the number. Get two or three of them wrong and the £8,500 could be £850, or £25,000.
A number is not a valuation
Even with every fact settled, there’s still the question of what the number is for.
A valuation for insurance asks what it would cost to replace your piece with one of the same quality. A valuation for selling asks what someone would actually pay for it today. Probate and family division ask different questions again. The same ring can have very different values depending on the purpose, and all of them can be correct.
Then comes the most important question of all: who is prepared to put their name underneath the answer?
It’s telling that GIA, the most respected gem grading laboratory in the world, identifies and grades stones but deliberately does not value them. Grading is evidence. Valuation is a judgement made from that evidence, for a stated purpose, by someone who can be asked to explain it.
Where AI does help
I’m not against AI. I use it every day, and I think it’s one of the most exciting developments our trade has seen in years.
In the laboratory it’s already proving its worth. GIA researchers have shown that machine learning can help classify difficult gem materials, and it cut by more than half the number of stones that conventional testing had to leave as “undetermined”. That’s a real gain, and it makes gemmology better, not less necessary.
The same researchers sounded a warning too. Even a one per cent error rate, repeated thousands of times, produces a great many wrong answers. One per cent sounds small until the wrong answer is on your insurance document.
Used well, technology helps a valuer keep better records, check their work and stay consistent. The International Valuation Standards Council reached the same view: AI is changing valuation, but it cannot replace the valuer. It works for the person holding the jewellery. It doesn’t replace them.
What a proper valuation includes
When you bring a piece to us for a valuation, it’s examined in the shop by our registered valuers. We:
- identify every stone, and test whether diamonds are natural or laboratory-grown;
- measure and weigh the stones, and grade their colour and clarity under proper conditions;
- look for treatments, and record anything that affects value;
- test the metal and read the hallmarks;
- note the condition honestly, including anything that needs attention;
- photograph the piece and write a full description;
- state the purpose of the valuation, the value, and the name of the valuer who stands behind it.
That last line is the whole point. Your insurer, and you, can see exactly who made the judgement and why.
Quick answers
Is an online or app valuation good enough for insurance? Rarely. Most insurers need a detailed written valuation from a qualified valuer who has examined the piece. Check your policy, and if in doubt, ask us.
Can AI tell a natural diamond from a lab-grown one from a photo? No. The two can look identical. Telling them apart needs testing, and that can only happen with the stone in hand.
How often should I have my jewellery revalued? Every few years, or sooner if gold and gemstone prices move sharply, so you’re never underinsured.
The best of both
AI will keep getting better at recognising jewellery and searching the market, and much of that is welcome. But a number from a photograph is a starting point, not an answer. When it matters, for your insurance, for your family or for a decision about selling, you want someone who has held the piece to tell you what it is and what it’s worth, and to sign their name to it.
That’s what we’ve done for twenty-two years.
By Simon Johnson FGA, gemmologist and diamond grader, former Fellow of the Institute of Registered Valuers and former Chairman of the National Association of Jewellers.
