Selling a diamond without a certificate: what does it cost you?
By far the most diamonds in Dutch jewellery have no papers. That is not a problem – it only changes who carries the risk, and you see that back in the offer.
Why a certificate raises the offer
A report from GIA, IGI or HRD sets down what the stone is: the weight in carats, the colour, the clarity and the cut quality. Without that report the buyer has to estimate those four properties himself – and where he is in doubt, he calculates cautiously.
That is not ill will. With the naked eye you can judge colour within two grades at best, and clarity only under a tenfold loupe. A dealer who resells the stone has to allow for that.
Reckon on roughly 10 to 20 per cent difference between a certified and an uncertified stone of the same quality. With larger stones that rises, because one grade of colour difference makes far more difference there in absolute euros.
When is it worth having a certificate made after all?
A laboratory report in the Netherlands generally costs between 100 and 250 euros, depending on the weight and on the laboratory, plus a few weeks of waiting. Those costs do have to be earned back.
Rule of thumb: below roughly 0.50 carat it seldom pays off. The uplift you gain with papers is then smaller than the cost of the report. Above one carat it usually does work out, certainly if the stone looks clean and white.
- Below 0.50 ct – leave the certificate be; sell on valuation.
- 0.50 to 1.00 ct – a matter of arithmetic; have it valued without obligation first and decide afterwards.
- Above 1.00 ct – almost always worth the trouble, certainly with a good colour.
- Set in a piece of jewellery – a laboratory prefers to judge a loose stone; unsetting costs money and can damage the setting.
How we go about it without papers
Our gemmologist does not take the stone out of its setting. He measures the diameter, estimates the weight with the standard formula for brilliant cut, and judges colour and clarity under a controlled light source, alongside comparison stones.
What he finds, you follow as he goes: which colour group, which clarity class and where the uncertainty lies. If you do not agree with it, you simply take the stone home again.
Watch out for laboratory-grown diamond
Since roughly 2015, laboratory-grown diamonds have turned up more and more often in new jewellery. Chemically they are identical to natural diamond, but their trade value is a fraction of it – and that value has fallen sharply in recent years.
With the naked eye the difference cannot be seen. We therefore test every stone above 0.20 carat for its fluorescence pattern; that costs you nothing and prevents you from carrying away the wrong expectation.
- Troy ounce, gram and carat: the units side by sideThe world market reckons in troy ounces, your scales in grams and your jewellery in carats. With these three conversions you can check any offer yourself.Read on
- Krugerrand, Maple Leaf or Philharmonic: which one sells fastest?All three contain exactly one troy ounce of fine gold. What you get for them still differs – that lies in how well known they are, the fineness and how easily they scratch.Read on
- How does a buyer check whether gold is real?Magnet, acid test, specific gravity and X-ray. What each method does and does not prove – and why a stamp alone is never enough.Read on
Questions about selling a diamond without a certificate: what does it cost you
Is my diamond worthless without a certificate?
No. By far the greater part of the diamonds that are traded have no papers at all, so this is the normal situation rather than the exception. The offer does usually lie 10 to 20 per cent lower than for an identical certified stone.
Can I see for myself whether it is a real diamond?
Only to a limited extent. A diamond cannot be scratched with steel and does not mist up when you breathe on it. Zirconia and moissanite sometimes pass those tests as well, so only a measurement gives certainty. That measurement we carry out free of charge while you watch.
Do I have to have my diamond taken out of the ring?
Not for our valuation: our gemmologist measures and judges the stone while it sits in its setting. For a laboratory certificate you do, because laboratories only assess loose stones. Unsetting costs money and can damage the setting, so weigh that up first.
How do you recognise a laboratory-grown diamond?
With a fluorescence test and, where necessary, with spectroscopy. Many laboratory-grown diamonds moreover carry a microscopic inscription on the girdle. We test every stone above 0.20 carat in this way, free of charge, so that nobody leaves with the wrong expectation.
Does the gold of the ring count separately?
Yes. We work out the stone and the precious metal separately and then add them together, so that you can see where the amount comes from. That way you can also decide per part: sell everything, or keep the stone and sell only the gold.
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Still something unclear?
Ask it here. You will receive a personal reply by email, usually within one working day – no automated message and no phone call you did not ask for.
- An answer from a valuer, not from a template
- We keep your question so that you need not repeat anything
- No sales pitch afterwards
Rather just have it looked at?
A valuation is free and without obligation, at a location near you.