A parcel of lab-grown diamonds arrives with IGI reports tucked inside the pouches. Most retailers glance at the carat and the grade, then put the stone in the tray. A wholesale buyer who reads the whole sheet catches the stones that become chargebacks: the CVD stone with a faint brown tint not obvious in the photo, the stone graded without a cut grade, and the report number that does not match the girdle. This is how a modern IGI lab-grown report reads from top to bottom.
Header: report number, shape and measurements
The top block carries the report number (often a 10 or 11 digit code for IGI), the shape and cutting style (for example, "Round Brilliant"), and measurements in millimeters, such as 6.40 - 6.44 x 3.96 mm. The millimeter range tells you girdle roundness; a spread above 0.15 mm on a 6.4 mm stone signals a slightly out-of-round girdle that may seat poorly in a head. Carat weight is given to two decimals. Compare it to your invoice weight; a 0.01 ct gap after recut is normal, a 0.03 ct gap is not.
The origin statement: CVD or HPHT
This is the line that separates a lab-grown report from a natural one. IGI states the growth method: Chemical Vapor Deposition (CVD) or High Pressure High Temperature (HPHT). It also notes any post-growth treatment, such as "as-grown" versus "grown and treated" for color or clarity. CVD stones sometimes show a faint brownish or grayish tint that is corrected by high-pressure annealing; HPHT stones often show a stronger blue or gray cast from residual nickel. For a white-stone parcel, confirm the color grade was assigned after any treatment, and that the report says "lab-grown" in a way that cannot confuse a consumer.
Color, clarity and cut grades
Color runs D to Z on the same scale as natural diamond. Wholesale buyers serving white metal target D through F for top stock and G through J for value lines. Clarity runs FL, IF, VVS, VS, SI, I. Eye-clean VS-SI is the trade sweet spot; I1 and below needs disclosure. Unlike some natural reports, IGI applies a cut grade to round lab-grown stones and leaves fancy shapes to the proportions diagram. Read table percent, depth percent, crown angle and pavilion angle; the trade sweet spot for rounds is table 55-60 percent, depth 60-63 percent, crown 34-35 degrees, pavilion 40.6-41.0 degrees.
The inscription and online verification
IGI laser-inscribes the report number, the words "LAB-GROWN DIAMOND," and sometimes a supplier code on the girdle. Read it under 10x before accepting the parcel. IGI's online verification portal lets you enter the report number and confirm shape, carat, color and clarity match the paper. A report that cannot be pulled up online, or that pulls up different measurements, is a reject. IGI reporting standards are published at igi.org; the category is described on Wikipedia's lab-grown diamond entry.
Common defects that fail intake
Three defects show up in roughly 5 percent of trade parcels. First, the girdle inscription does not match the paper number, signaling a swapped stone or reused report. Second, the measured carat differs from the report by more than 0.02 ct, indicating a recut after grading. Third, the Comments box lists "additional treatment" that the supplier did not mention on the invoice. Photographing the report, the stone on a digital gauge, and the girdle inscription in one intake folder removes 90 percent of later disputes. For comparison, see how a GIA report reads and our note on GIA versus IGI for lab-grown parcels.
How CVD and HPHT change the finished look
The growth method quietly affects which customer the stone suits. CVD boule grows in layers, so cutters often saw thin slabs into several smaller stones; this keeps per-carat cost low and is why 1 to 2 ct CVD parcels flood the value end of the market. HPHT growth produces larger, more uniform crystals, which is why larger HPHT stones show up in premium white stock. The practical point for ordering: ask the mill which method a parcel was grown by, because it correlates with price band and with the faint tints described above. For how those grades map onto a buying decision, see the 4Cs explained for trade buyers.
FAQ
Is an IGI lab-grown certificate the same as a GIA one?
The 4Cs scales match, but IGI papers lab-grown stones routinely and states CVD or HPHT origin; GIA also grades lab-grown but is used less often on value-priced parcels.
Can I verify an IGI report online?
Yes. Enter the report number in IGI's verification portal and confirm shape, carat, color and clarity match the paper before you pay.
What does "as-grown" mean on an IGI report?
It means the stone was not treated after growth for color or clarity. "Grown and treated" means annealing or irradiation was applied, which must be disclosed.
Does IGI grade the cut on pear or oval stones?
No. Fancy shapes receive no cut grade; you read the proportions diagram and check measurements against the supplier's recommended head sizes.
Wholesale note: gemmanufacturer.com ships IGI lab-grown parcels with report numbers pre-registered in the verification portal, so buyers confirm every stone at intake instead of after delivery.
Related reading: Lab Grown Diamond IGI Certification Guide, Is Lab-Grown Diamond Real Diamond? Everything You Need To Know, Moissanite vs Diamond vs Lab-Grown: The Final Showdown.
