IGI Lab Grown Diamond Certificate vs IGI Natural Diamond Certificate: What Is Different

Pick up an IGI Lab Grown Diamond Report and an IGI Natural Diamond Report and lay them side by side. The 4Cs grading, the proportions diagram, the clarity plot, the polish and symmetry grades: all of it looks nearly identical. The real differences sit in three specific fields that appear only on the lab-grown version: an explicit “Laboratory-Grown” origin declaration, the growth method (CVD or HPHT), and a girdle laser inscription that permanently encodes the stone’s lab origin.

Those three additions exist because disclosure is a legal and ethical requirement, not a courtesy. A natural diamond report has no reason to name a growth method, because the stone formed in the earth over billions of years. A lab-grown report has to tell you exactly how it was made and confirm it was not mined. Everything else on the two documents follows the same grading standards, the same scales, and the same gemologist protocols.

What fields appear on both IGI reports?

Both the IGI Natural Diamond Report and the IGI Lab Grown Diamond Report share a common core. The document includes the stone’s shape and cutting style, precise measurements, and the full 4Cs assessment: carat weight, color grade on the D-to-Z scale, clarity grade at 10x magnification, and cut grade. Polish and symmetry are graded for every shape. Round brilliant stones receive an overall cut grade derived from IGI’s brightness, fire, scintillation, and pattern studies. Fancy shapes go through a four-step system that combines finish, proportions, shape-specific requirements, and light return.

Color grading on both reports uses the same blind, parallel process: multiple gemologists submit independent opinions without collaborating, and the grade is confirmed only when enough opinions agree. Clarity grading follows the same FL-to-I3 scale and the same 10x magnification standard for both origin types.

The table below shows the shared fields at a glance.

What fields are unique to the IGI lab grown diamond certificate?

Three fields appear on the lab-grown report that have no equivalent on the natural report.

Origin declaration

The IGI Lab Grown Diamond Report explicitly states the stone is “Laboratory-Grown.” This label is not optional. IGI screens every stone using advanced spectroscopic technology to confirm whether it is naturally mined, laboratory grown, or a simulant, and the result of that screening is printed on the face of the report. The natural diamond report carries no such declaration, because the origin screen already cleared it as mined.

Growth method disclosure

The lab-grown report names the production process: either CVD (Chemical Vapor Deposition) or HPHT (High Pressure High Temperature). This field appears in the comments section of the IGI lab-grown report upon request, though most retailers ask for it as standard practice. The natural report has no growth method field at all, for obvious reasons.

Why does the method matter? CVD diamonds sometimes require post-growth treatment to correct residual color, and if that treatment is significant, IGI notes it alongside the growth method. HPHT stones tend to show different fluorescence patterns. Neither method produces a chemically inferior stone: both CVD and HPHT lab-grown diamonds are physically, chemically, and optically identical to mined diamonds. But knowing which process was used gives buyers a complete picture.

Girdle laser inscription encoding lab origin

Both report types can carry a laser inscription on the girdle that matches the report number. The distinction is that for lab-grown diamonds, IGI’s inscription automatically encodes the stone’s laboratory-grown origin as part of the inscription. This inscription is invisible without magnification but readable with a loupe, and it permanently links the physical stone to its certificate so the origin cannot be separated from the gem after purchase.

The table below isolates the three lab-only fields.

Does the grading scale differ between the two reports?

No. IGI applies the same D-to-Z color scale and the same FL-to-I3 clarity scale to both natural and lab-grown stones. The grading methodology, the viewing conditions, the magnification standard, and the blind multi-grader process are identical across both report types.

One thing worth knowing: IGI’s grading tends to run slightly more generous than GIA’s for both color and clarity. Trade publications covering diamond grading have noted this gap at approximately one grade on average, and it applies to both natural and lab-grown IGI reports equally, so it is not a lab-specific issue. Buyers setting quality targets should factor that in. Industry resellers commonly suggest aiming for VVS2 clarity or higher and E color or higher when shopping IGI-certified lab-grown stones, to land closer to the equivalent of a GIA VS1/F stone.

As of October 2025, GIA replaced its full 4Cs grading for lab-grown diamonds with a simplified two-tier system that labels stones only as “Premium” or “Standard,” meaning specific grades like “D color” or “VVS2 clarity” no longer appear on GIA’s lab-grown reports. IGI continues to issue the full D-to-Z and FL-to-I3 grades for every lab-grown stone it certifies, which makes IGI the practical standard for anyone who needs a precise, comparable grade on a lab-grown diamond in 2026.

How do you verify either IGI report before buying?

Both report types carry a unique report number. For lab-grown reports, the number typically begins with the prefix “LG.” You can verify any IGI report free of charge on IGI’s official website in under a minute. The verification confirms that the report number, the 4Cs grades, and the origin declaration on the physical document match what IGI has on file.

For lab-grown diamonds, also check that the girdle inscription number matches the report number under a loupe or jeweler’s magnifying glass. If a seller cannot produce the original certificate or the inscription number does not match, treat that as a serious warning sign. When shopping for IGI-certified lab-grown diamonds, confirm that all three lab-specific fields (origin declaration, growth method, and lab-origin inscription) appear on the report before completing any purchase.

The Origin Field Is What Separates the Two Reports

The 4Cs grading on an IGI lab-grown certificate and an IGI natural diamond certificate follows the same scales, the same methodology, and the same multi-grader blind process. The practical difference comes down to three fields that appear only on the lab-grown report: the “Laboratory-Grown” origin declaration, the CVD or HPHT growth method notation, and the lab-origin girdle inscription. Those fields exist because buyers have a right to know exactly what they are purchasing, and because selling a lab-grown diamond without origin disclosure is a trade violation in most markets. Before buying any IGI-certified lab-grown stone, verify all three fields are present on the report. Retailers who include the full IGI report with every purchase, with no need to request it separately, are the simplest way to confirm you have complete documentation from day one. Ouros Jewels operates that way across its lab-grown diamond jewelry collection.

Frequently Asked Questions

Does an IGI lab grown diamond certificate cost more than a natural diamond certificate?

The certification fee for a lab-grown IGI report is generally lower than for a natural diamond report of equivalent carat weight, partly because IGI built dedicated lab-grown grading infrastructure near major manufacturing hubs, which reduces processing time and cost. That saving typically passes through to the buyer in the form of a lower total purchase price.

Can a jeweler swap a natural diamond into a lab-grown diamond setting and change the IGI certificate?

No. The IGI report number is laser-inscribed on the stone’s girdle and tied permanently to the stone’s recorded characteristics. Swapping a stone breaks the match between inscription and certificate. Any reputable jeweler or appraiser can verify the match in seconds under magnification, making this type of substitution immediately detectable.

What does “growth method not specified” mean on an IGI lab grown certificate?

Some older or lower-tier IGI lab-grown reports were issued before growth method disclosure became standard practice. If your report lacks a CVD or HPHT notation and was issued before 2022, it may simply predate the current disclosure norms. For any certificate issued in 2024 or later, the absence of a growth method field is worth querying with the seller before purchase.

Is an IGI lab grown diamond certificate accepted by insurance companies in the United States?

Yes. IGI reports, for both natural and lab-grown diamonds, are accepted by most US-based jewelry insurers and appraisers as valid documentation of a stone’s characteristics and value. The insurer will typically use the 4Cs grades and carat weight from the IGI report to set the replacement value for your policy.

If a lab grown diamond has post-growth treatment, where does IGI disclose it on the certificate?

IGI notes significant post-growth treatments in the comments section of the lab-grown grading report. For CVD diamonds that underwent HPHT decolorization to improve color, that treatment will appear alongside the growth method notation. The natural diamond report uses the same comments section for treatment disclosure, but it will never reference a growth method.