A grading report is an independent laboratory's description of a diamond. It is not an appraisal of value. Here is how lab-grown diamonds are graded and how we describe them.
The 4Cs
- Each lab-grown diamond is graded for Carat weight, Color (D = colorless, down the alphabet), Clarity (FL/IF, VVS1–VVS2, VS1–VS2, SI1–SI2, I1–I3) and, for round brilliants, Cut (Ideal / Excellent down to Poor), plus polish, symmetry, fluorescence and measurements.
- Grading reports state that the diamond is laboratory-grown and often name the growth method (CVD or HPHT) and any post-growth treatment.
- The report number is often laser-inscribed on the girdle (the stone's thin outer edge). On lab-grown stones it is typically preceded by "LG".
GIA (Gemological Institute of America)
Since 1 October 2025, GIA no longer uses the 4C color and clarity scales for laboratory-grown diamonds in the D-to-Z color range. Its "Laboratory-Grown Diamond" service now places qualifying stones into one of two descriptive categories:
- Premium: D color, VVS clarity or higher, and Excellent polish, symmetry and (for round brilliants) cut.
- Standard: E to J color, VS clarity or higher, and Very Good or better polish, symmetry and cut.
Stones that fall below the Standard category don't receive a GIA assessment. GIA laser-inscribes qualifying stones with "Laboratory-Grown" and the report number. (Source: GIA press release, 26 Aug 2025.)
What this means for Nuvé listings
- Grading report details are provided where available. Where a listing includes grading details, they appear on the product page.
- Where a listing gives a target range for accent stones (for example "F–G color, VS clarity"), those stones are selected to that range and are not individually graded. This is normal for small accent stones in pavé, tennis and eternity designs.
- If we ever offer GIA-assessed stones, we'll list the GIA category (Premium or Standard), not 4C color and clarity grades.
Quick glossary
- ctw: carat total weight, the combined weight of all diamonds in a piece.
- CVD / HPHT: the two main ways laboratory-grown diamonds are grown.
- Girdle inscription: microscopic laser lettering on the edge of the diamond, visible with a loupe.