Ask the seller for the IGI report number, look it up on igi.org, and check that the grades match what you were sold. Then read the girdle inscription on the stone under a 10x loupe and confirm it matches that same number. Two steps, both free, both done without leaving home.
Where is the laser inscription, and can you see it?
The inscription sits on the girdle, the thin outer rim where the top half of the stone meets the bottom. It is cut by laser and it is microscopic. You will not see it with the naked eye, and you will not see it in a phone photo taken at arm's length. You need roughly 10x magnification: a jeweller's loupe, a decent USB microscope, or a jeweller who will put the stone under a scope while you watch. IGI explains the process on its Laserscribe service page.
Inscription is standard practice on IGI-certified lab-grown stones rather than a universal law of the industry, so the honest question to ask a seller is simply whether this particular stone carries one. At Carat Club Co. the inscription is stated explicitly on the product pages where it applies, so you know before you buy whether there is a serial to match.
Essential Diamond Solitaire Studs
From HK$2,300
Individually IGI-certified and laser-inscribed with a serial number verifiable in IGI's public database. Stones run from 0.5ct to 2.0ct, so every stone in this line is one you can check both ways.
How do you check the report number step by step?
- Get the report number before you pay, not after. A seller who is certifying stones has the number on file and can send it in a message. If the answer is that the certificate comes later, ask when and what the number will be.
- Go to igi.org and use IGI's own report lookup. Type the number in yourself rather than clicking a link the seller sent you, so you know which site you are actually on.
- Read the report against the listing. Carat weight, colour, clarity, cut, shape, and the fact that the stone is described as laboratory-grown should all match what the product page says. A mismatch on carat weight or clarity is the one worth stopping over.
- Check the report is for a single stone, not a piece of jewellery. Most stone reports grade the loose diamond before setting. IGI describes what goes on a lab-grown report on its lab-grown diamond report page.
- When the piece arrives, put the stone under 10x magnification and rotate it slowly. The inscription runs along the girdle, so it comes into view at one particular angle and disappears at others.
- Compare the inscription to the report number you looked up. Same number, and the report in your hand is the report for the stone in your hand.
Vanguard Men's Diamond Solitaire Studs
From HK$1,599
Individually IGI-certified and laser-inscribed with a serial you can verify online. Stones start at 0.5ct, which is the point where independent grading is worth what it costs.
The step most buyers skip
Looking up the number on IGI's site proves one thing: that report exists and carries those grades. It does not, on its own, prove anything about the diamond sitting in your hand. The inscription is what ties the two together. Most buyers do the online lookup, see a real report, feel satisfied, and never look at the girdle. If you are only going to do one of the two checks, the loupe is the one that closes the loop.
What a certificate does not do
A report grades and identifies a stone. It does not price it. Two stones with identical grades can be sold at very different prices, and nothing on the report tells you which price is fair, so a certificate is not a valuation and should not be read as one. It also says nothing about condition after the stone leaves the lab: it is a grading document, not a warranty. If you want the differences between the two labs most often quoted on lab-grown stones, we set them out in IGI versus GIA.
When is having no certificate perfectly normal?
Below 0.5ct, independent grading usually costs more than the stone. That is why stones under half a carat are not certified by default at Carat Club Co., with certification available on request for anyone who wants it. Within a single piece the rule applies per stone, so a 1.0ct centre stone can be certified while a 0.1ct accent beside it is not.
A stone with no certificate is not a red flag by itself, as long as the seller states the position up front and prices accordingly. The red flag is the opposite case: a seller who claims certification and then cannot produce a number you can check. More on the small-stone case in whether studs come with a certificate.
Origin Diamond Solitaire Studs
From HK$999
Origin ships without an IGI certificate as standard, to hold the entry price; certification is available on request. This is the honest version of a piece with nothing to verify: no number is claimed, so no number is missing.
What about a bracelet with 34 stones?
Multi-stone pieces are where certification economics turn strange. A 17cm tennis bracelet set with 0.5ct stones holds 34 stones. At HK$350 per stone, documenting the full line adds HK$11,900, close to the entry price of the bracelet itself. That is why certificates are not bundled into tennis bracelet pricing, and why a shop that implies they are is worth a question.
Seamless Diamond Tennis Bracelet
From HK$13,500
The listed price does not include IGI certificates; each stone can be documented individually at HK$350 per stone on request. Certify one stone as a sample, certify the lot, or skip it, but the arithmetic is yours to see.
FAQ
Can I read the inscription with my phone camera?
Not reliably. Phone macro modes get close but the inscription is cut at a scale meant for a loupe. Clip-on 10x macro lenses sometimes work on a loose stone and rarely work on a set one. A jeweller with a scope will do it in under a minute.
What if the report number checks out online but the stone has no inscription I can find?
Rotate the stone fully first, because the inscription is easy to miss at the wrong angle, and try again with better light. If it is genuinely not there, ask the seller directly whether that stone was inscribed. The answer should be a straight yes or no.
I lost the paper certificate. What can I do?
If the stone is inscribed, the number on the girdle is still there and you can look the report up again on IGI's site. For the physical document, contact us and ask what is possible for your order. That is an ask, not a promise.
Does a certificate mean the diamond is worth what I paid?
No. It confirms the grades and identifies the stone. Price comes from the seller, not the lab. Use the report to check you received the stone you were sold, then compare prices across sellers for the same grades to judge whether the number on the tag is reasonable.
