The Heritage & Co. Stone Grading Standard
Our standard grade for centre stones, verified by the two grading laboratories we accept: IGI for lab-grown diamond, GRA for moissanite.
The standard
Our standard centre stone, lab-grown diamond or moissanite, is graded to the specification below. Some lab-grown diamond designs also offer F colour, VS2 clarity at a lower price, and other grades can be sourced on request. The grade of every stone is stated on its original lab report.
| Attribute | Heritage & Co. standard | What it means |
|---|---|---|
| Colour | D | The highest colourless grade. No yellow or brown tint, even to a trained eye. |
| Clarity | VVS1 | Very, very slightly included. Inclusions are extremely difficult to see even under 10× magnification. |
| Cut | Excellent | The highest cut grade. Optimal light return, fire, and scintillation. |
D/VVS1/Excellent is the standard for both our lab-grown diamonds (IGI graded) and our moissanite (GRA graded). Where a design offers a lower grade, it is shown on the product page and stated on the stone's report.
The laboratories we use
International Gemological Institute (IGI)
Used for: every Heritage & Co. lab-grown diamond.
IGI is one of the world's largest and oldest gemmological institutes, with grading laboratories in Mumbai, Surat, Antwerp, New York, Hong Kong, and elsewhere. It is the primary grading authority for lab-grown diamonds worldwide and the only major lab that issues a full cut grade on every fancy shape — not only round brilliant.
An IGI report includes the full 4Cs (carat, colour, clarity, cut) plus symmetry, polish, fluorescence, measurements, and a proportions diagram. Every report is tied to the stone by a unique report number laser-engraved on the diamond's girdle at microscope scale — invisible to the naked eye, permanent, and uniquely matched to the report.
Why we accept IGI: it issues full per-stone 4Cs grading on every shape, which is what verification requires. We do not accept lab-grown diamonds without an IGI report.
Gemological Research Association (GRA)
Used for: every Heritage & Co. moissanite.
GRA is the internationally recognised grading standard for moissanite. Every Heritage & Co. moissanite is supplied with its original GRA report.
A GRA report confirms the stone is moissanite (not cubic zirconia or another simulant), documents its carat weight and dimensions, and grades its colour, clarity and cut. Each report carries a unique serial number paired to the stone.
Why we accept GRA: it is the lab consistently used across the moissanite trade, it grades colour, clarity, and cut, and its reports can be verified by serial number. We do not accept moissanite without a GRA report.
Why not GIA for lab-grown diamond?
As of 1 October 2025, GIA (the Gemological Institute of America) stopped issuing individual 4Cs grades for lab-grown diamonds. Every lab-grown diamond submitted to GIA now receives a simplified Premium / Standard classification rather than individual colour, clarity, and cut grades.
That shift removed exactly the per-stone verification detail that Heritage & Co. needs. A GIA Premium stamp does not distinguish between a D colour, VVS1 clarity, Excellent cut diamond and a stone several grades below that.
IGI continues to issue full 4Cs reports on every lab-grown diamond, including cut grade on every fancy shape. That is why IGI is the only lab we accept for lab-grown diamonds.
How every stone reaches the Heritage & Co. standard
- Sourcing. Stones are sourced from suppliers whose reports consistently match IGI (lab diamond) or GRA (moissanite) grading.
- Grade gate. Every stone must arrive with a report that confirms the grade ordered. Anything that does not match is rejected.
- Report matching. Each stone is matched to its original lab report by its girdle laser engraving (lab diamond) or serial (moissanite) before setting.
- Ring ships with report. Every engagement ring leaves us with the original lab report in the packaging.
If a stone's report does not confirm the grade you ordered, the stone does not go in a Heritage & Co. ring.
See how to verify the stone in your own ring on our Stone Verification page, or explore our engagement ring collection.
