Every certified diamond comes with a unique report number from its grading laboratory, and if your stone was graded by the International Gemological Institute, running an IGI report number check is the fastest way to confirm exactly what you’re buying. It takes less than a minute, costs nothing, and gives you direct access to your diamond’s grading details straight from IGI’s own database.

At A Star Diamonds, we work with both natural and lab-grown certified diamonds at our Hatton Garden workshop, and we encourage every customer to verify their stone’s report independently. It’s a simple step that builds genuine confidence in your purchase, whether you’re choosing an engagement ring with us or evaluating a diamond from any other source.

This guide walks you through the exact process: where to go, what to enter, how to read the results, and what to do if something doesn’t look right.

What an IGI report number check confirms

When you complete an IGI report number check, you get a direct view of the information IGI recorded at the time of grading. This is not a summary from a retailer or a certificate copy; it is IGI’s own live database entry for that specific stone.

Accessing IGI’s database directly means you’re reading the original grading data, not an interpretation of it.

The grading details you can confirm

The IGI report covers the four key characteristics of any diamond: carat weight, colour grade, clarity grade, and cut grade. For lab-grown diamonds, it also confirms the growth method (HPHT or CVD), which affects how the stone was produced. Each of these values is recorded at the time of grading and does not change after the report is issued.

A typical IGI diamond report includes:

• Carat weight: measured to two decimal places
• Colour grade: on a scale from D (colourless) to Z
• Clarity grade: from FL (flawless) to I3
• Cut grade: covering cut, polish, and symmetry for round brilliants
• Shape and measurements: the stone’s dimensions in millimetres
• Fluorescence: how the diamond responds to UV light
• Growth type (lab-grown only): HPHT or CVD

What it tells you about authenticity

Your report check also confirms whether the report number itself is genuine. If someone has altered a physical certificate or is presenting a certificate that belongs to a different stone, the online record will show different grading details. This is one of the most practical ways to catch a misrepresented diamond before you complete a purchase.

For engagement ring buyers in particular, this step carries real weight. A verified report gives you confidence that the carat weight and quality grades you’re paying for are the ones IGI actually assigned to your stone.

Get the report number and key details first

Before you run an IGI report number check, you need the report number itself and a few details from your diamond to compare against the online record. Having these ready before you open the verification tool makes the process faster and the comparison more thorough.

Where to find your IGI report number

Your report number appears in several places. On a physical IGI certificate, it sits at the top of the document, typically printed prominently. For a laser-inscribed diamond, the same number is engraved on the stone’s girdle (the narrow band around its widest point), visible under 10x magnification at any jeweller. Digital certificates sent by email carry the number in the PDF header.

If you have a physical certificate, confirm that the number printed on the document matches the laser inscription on the girdle before you verify anything online.

Before opening the IGI tool, note down:

• The report number (usually 9 to 15 digits)
• The carat weight shown on your certificate
• The colour and clarity grades listed

Having these three details ready lets you cross-reference the online result line by line, rather than simply confirming the number exists.

Verify the report number on the official IGI tool

The official IGI verification tool is available at igi.org. Navigate to the report check section, enter your report number into the search field, and click verify. Your results load within seconds, pulled directly from IGI’s live database, giving you the same grading information IGI recorded when they assessed the stone.

Use IGI’s own tool for your igi report number check rather than third-party aggregators, which may show outdated or incomplete data.

What to enter and what to expect

Your search field accepts the report number only, with no spaces, hyphens, or additional characters. Enter the digits exactly as they appear on your certificate, then submit. The results page displays all grading details IGI recorded for that stone: carat weight, colour, clarity, cut, fluorescence, and for lab-grown diamonds, the growth method.

Use this quick reference before you enter the number:

If the tool returns no result, double-check you copied the full number accurately before moving to the troubleshooting steps in the next section.

Match the online report to your diamond or jewellery

Once your IGI report number check returns results, the real work begins: comparing what the screen shows against the physical stone or certificate in front of you. A report number that returns valid results does not automatically mean the diamond in your hands matches that record. You need to verify each grading detail point by point.

Check the grading details line by line

Pull out your certificate and compare every graded characteristic against the online record. Start with carat weight, then colour, clarity, and cut. These values must match exactly. Even a single discrepancy, such as a colour grade of F online versus E on the certificate, is worth investigating before you proceed with any purchase.

If any detail differs between the online record and your certificate, contact the seller directly before completing the transaction.

Use this checklist to work through the comparison systematically:

• Carat weight: matches to two decimal places
• Colour and clarity: identical grades on both
• Cut, polish, symmetry: all three align
• Shape and measurements: dimensions match the certificate

Confirm the laser inscription on the girdle

For any laser-inscribed diamond, ask your jeweller to view the girdle under 10x magnification. The inscription number should match both your certificate and the online record exactly. This three-way match between the stone, the certificate, and IGI’s database gives you the strongest possible confirmation that the diamond is correctly identified.

If the IGI check does not work or looks wrong

An unsuccessful search or a mismatched result does not always mean something is wrong with the diamond, but both situations require a clear next step before you proceed with any purchase.

When the report number returns no result

If your igi report number check returns nothing, re-enter the number manually rather than copying and pasting, since hidden characters can cause failed searches. Check that you are using the full number from the top of the certificate, not a retailer’s reference number. Very recently issued reports can take 24 to 48 hours to appear in IGI’s live database, so retrying after a day is worth doing.

If the number still returns no result after 48 hours, ask the seller to provide a direct explanation before the transaction continues.

When the details do not match your certificate

A grading discrepancy between the online record and your certificate means one of two things: the certificate has been altered, or the wrong stone has been paired with it. Note every mismatched detail before you contact the seller. Follow these steps if the details do not align:

• Record every discrepancy in writing with the exact values from both sources
• Contact the seller directly and request a formal explanation
• Ask an independent gemologist to examine the stone if the seller cannot resolve the issue

Quick recap and what to do next

Running an igi report number check takes under a minute and gives you direct access to your diamond’s official grading record from IGI’s own database. Start with the report number from your certificate, enter it at igi.org, and compare every grading detail against both your physical certificate and the laser inscription on the girdle. If everything aligns, you have strong confirmation that your stone matches its certification.

If anything looks wrong, note every discrepancy, contact the seller, and bring in an independent gemologist if needed. These steps protect you before money changes hands, not after.

Buying a certified diamond should feel straightforward, not stressful. At A Star Diamonds, every stone we use comes with full certification, and we walk you through the verification process together. Book a consultation with our team and we’ll help you choose a diamond you can trust completely.