MAYLAYA GEMS · THE DIAMOND EDIT
Updated 27 September 2026 · By Maylaya Gems
Searching for a GIA or IGI lab-grown diamond certificate? Start with what the document actually tells you. Shoppers often call it a certificate; here we distinguish a grading report from an overall quality assessment. Maylaya Gems favours IGI’s individual grading detail for customers who want to compare specifications clearly. That preference concerns the information available to the buyer, rather than a claim that every IGI-reported diamond is better.
Which reports are we comparing?
This guide focuses on loose, colourless to near-colourless laboratory-grown diamonds. GIA lists a current quality-assessment service for eligible stones of at least 0.15 carat, while its coloured lab-grown diamond services are separate. Jewellery reports and historical report formats also need separate consideration. Do not apply this comparison to every document bearing either laboratory’s name. [1]
What information does an IGI report provide?
IGI continues to use the 4Cs for laboratory-grown diamonds. A report identifies the diamond’s origin and records shape, measurements, carat weight, colour and clarity; cut reporting depends on the relevant service and stone. Depending on report format, proportions and clarity diagrams may also be present. Check the document you are actually receiving rather than assuming every report contains the same diagrams. [3],[5]
What changed in GIA’s lab-grown diamond assessment?
GIA introduced its revised D-to-Z service on 1 October 2025. Its current result is an overall category based on several quality criteria, rather than the individual colour and clarity grades familiar from earlier reports. A stone must meet the assessment’s minimum requirements to receive a result. The category is meaningful, but it is not a one-to-one replacement for a specific colour-and-clarity combination. [2]
Understanding GIA Premium and Standard
Premium requires D colour, VVS clarity or higher, excellent polish and symmetry, and excellent cut for round brilliants. Standard permits combinations of Premium attributes and the lower qualifying thresholds: E–J colour, VS clarity, very good polish, very good symmetry (good for fancy shapes), and very good cut for rounds. A stone below a minimum threshold does not receive the assessment. [2]
GIA vs IGI: comparison at a glance
| Information | IGI laboratory-grown report | Current GIA quality assessment |
|---|---|---|
| Colour and clarity | Individual grades help distinguish specifications. | A combined quality category; not the same individual-grade presentation. |
| Primary comparison benefit | Useful for a brief with separate grade requirements. | Useful for checking whether the stone meets category criteria. |
| Cut-related information | Check cut grade/service, polish, symmetry and proportions on the actual report. | Cut and finish criteria contribute to eligibility and category. |
| Exceptions to remember | Fields and diagrams vary with report and service. | Older LGDR and coloured-diamond reports use other formats. |
Why we favour IGI for detailed comparisons
A buyer may have a specific brief: a particular shape, a colour preference, a clarity target and a total budget. Individual grades let the buyer check those requirements separately. This is the practical advantage we value in IGI reporting: it makes the conversation about the proposed stone more precise. It does not remove the need to see the diamond, understand the setting or compare the full quotation.
Read cut, polish and symmetry separately
A shape describes the outline or cutting style; a cut assessment addresses additional performance or proportion criteria. IGI describes cut assessment for round brilliants and a separate approach for fancy shapes. Its reports also record polish and symmetry. Ask which cut service applies to your chosen stone. Do not treat excellent polish and symmetry alone as proof of an excellent overall cut. [4]
What about CVD, HPHT and treatments?
IGI states that growth process and the presence of treatments can be recorded in report comments upon request. Look for the actual wording rather than assuming that every report includes it. Ask the jeweller to explain any entry you do not understand and to confirm it refers to the stone being offered. A growth-method label on its own should not replace a careful comparison of the finished diamond. [4]
Why an older GIA report can look different
GIA’s earlier LGDR formats included detailed 4Cs information, and some included growth and treatment disclosures. Such documents remain in circulation. The 2025 service change is not a reason to describe every earlier report as incomplete or invalid. Check the date, report type and laboratory record before deciding what information a particular document provides. [6]
Which report should you choose?
If your priority is comparing individual colour and clarity grades, IGI is a particularly useful choice. If you are considering a GIA-assessed stone, ask what the stated category establishes and what additional information you need. In either case, buy the actual diamond and the agreed jewellery specification—not a laboratory name alone. A report does not promise a particular resale price or guarantee that you will prefer the stone’s appearance.
Five checks before ordering
- Request the complete report, including its date and comments—not only a cropped screenshot.
- Verify the report number through the issuing laboratory’s official report-check service.
- Ask the jeweller to match the document to the stone, including any inscription and measurements; a matching online number alone does not physically authenticate a diamond.
- Request a video of the actual diamond under more than one lighting condition.
- Confirm the diamond specification, metal, ring size, total price, delivery estimate and after-sales terms in writing.
Frequently asked questions
Is IGI better than GIA for lab-grown diamonds?
IGI is especially useful when you want individual grades for a detailed comparison. That reporting advantage does not establish that every IGI-reported diamond is more beautiful or more valuable.
Does GIA still assess lab-grown diamonds?
Yes. Its current service includes a quality assessment for eligible colourless to near-colourless loose lab-grown stones, alongside separate coloured-diamond services. [1]
Does Standard mean a bad diamond?
No. It is a defined GIA category, not a statement that a buyer will dislike the stone. Ask how the actual diamond meets your preferences and budget.
Can I convert Premium into an IGI grade?
Do not use it as an automatic cross-laboratory conversion. Read the category criteria and the individual report, and request the information you need.
Does a centre-stone report cover every diamond in a ring?
Do not assume so. Ask which stone or stones the document describes. Mounted-jewellery reports have a different scope, and assessments can be limited by the setting. [4]