Diamond certificates: what GIA, HRD and IGI do
At the counter it is the most frequent question about diamond: do I need that piece of paper? The answer has more to it than yes or no, and it helps to know what such a report actually is — and above all what it is not.
A laboratory measures, it does not value
A certificate from GIA, HRD or IGI describes your stone: weight, cut and proportions, colour, clarity, fluorescence and the exact dimensions. What it deliberately does not contain is a figure. Laboratories do not value, they measure. The value follows afterwards, from those measurements and from the market of the moment.
That distinction is the whole point. A report takes the uncertainty out of a valuation, and uncertainty is precisely what pushes an offer down. If a buyer has to establish for himself whether he is looking at a G or a J, he will price that doubt against you — not out of ill will, but because he carries the risk.
The three names are not interchangeable. GIA counts worldwide as the strictest yardstick. HRD sits in Antwerp and is strongly represented in the Benelux. IGI you see a great deal with jewellery and smaller stones. Where a laboratory grades more loosely, we apply a correction and show you that correction, rather than folding it silently into the offer.
Why we look at the girdle first
A certificate is only worth something if it demonstrably concerns this stone. Many certified diamonds therefore carry a laser inscription on the girdle: the report number, legible only under magnification. That is the first thing we compare.
GIA, HRD and IGI also keep public registers. With the report number you can check on the laboratory's own site whether the document is genuine and what it said when it was drawn up. Do that at home beforehand and you know where you stand before your visit. We do it during the valuation in any case.
Lost the certificate but still know the number? Then nothing is lost. With the report number we retrieve the details from the public register and the report counts in full.
From what weight does a certificate pay for itself?
A carat is exactly 0.2 grams, and the trade counts in hundredths of one. As a rule of thumb: below roughly half a carat a certificate rarely repays the cost of having it drawn up. Above that it depends on the quality of the stone and on your plans for selling.
What you do not need to do is have a report made before you come in. Our gemmologists measure the stone without papers too, and also while it is still in its setting. If that measurement shows a certificate would pay off in your case, we say so — even where that means you do not sell yet.
And the setting counts separately. We weigh it on weight and fineness against the gold rate of the moment: on 14 August gold stood at 120.99 euros per gram, 6.4 per cent above the 113.74 euros of 28 July. About the diamond market we deliberately make no statement here — we measure precious metal rates, not stones, and what we do not measure we do not write down.
- Gold at 120.55 euros per gram: up 5.4%, 6.6% below the topGold stands higher than six weeks ago but below the 129.04 euro peak of late August. Both figures, the sum behind them, and what you can do with it.Read on
- The four Cs: which weighs heaviest when selling?Carat, cut, colour and clarity are not equally important. Which is measurable, which remains a judgement, and why an old cut deserves its own yardstick.Read on
- Selling a watch without papers: can you?Yes, and we buy it too. What gets checked in place of a warranty card, which numbers sit inside the case, and what you can look up at home beforehand.Read on
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
Sources
Where you can verify what you have just read.
- LBMAThe London gold and silver price our daily rate is built on
- WaarborgHollandThe Dutch assay office that verifies fineness and strikes hallmarks
Rather just have it looked at?
A valuation is free and without obligation, at a location near you.