The Gemological Institute of America (GIA) is globally recognized as the strictest and most respected independent diamond grading authority. Every GIA certificate evaluates a diamond across four criteria — the "4 Cs".
Cut
Cut determines how much light a diamond reflects, and therefore its brilliance. It's the only one of the 4 Cs directly shaped by human craftsmanship.
Color
Graded on a scale from D (colorless) to Z (noticeably yellow). For natural white diamonds, the more colorless, the more valuable.
Clarity
Measures internal inclusions and external characteristics, from "Flawless" to "Included". Fewer inclusions mean better light performance.
Carat
The diamond's weight — one carat equals 0.2 grams. Carat alone doesn't determine quality; it only matters in combination with the other three Cs.
Why this matters for STIG GROUP buyers
Every diamond traded through STIG INTERNATIONAL carries a GIA certificate — creating transparency and an objectively verifiable value, the foundation for structured diamond ownership through STIG ROCK.