Diamond colour scale
GIA grades diamond colour from D (totally colourless) to Z (light yellow or brown). Beyond Z, the diamond enters the realm of fancy coloured diamonds.
Colour is graded by comparing the diamond face-down against master comparison stones. The differences between adjacent grades are subtle — distinguishing a D from an F requires expert training and a controlled lighting environment.
What the grades mean visually
- D, E, F (Colourless) — Highest grades. No detectable colour even to a trained eye. Significant price premium.
- G, H (Near-Colourless) — Visually indistinguishable from colourless to the untrained eye. Excellent value.
- I, J (Near-Colourless) — Slight warmth visible under direct lighting if you know what to look for. Strong value.
- K and lower — Visible warmth. Often paired with yellow gold, where the warmth complements the metal.
For most buyers, G or H is the sweet spot. For yellow gold settings, I or J can be ideal — the warmth disappears against the metal.
Diamond clarity scale
Clarity grades range from Flawless (FL) at the top to Included (I3) at the bottom:
- FL, IF — Flawless or Internally Flawless. Vanishingly rare and priced accordingly.
- VVS1, VVS2 — Very Very Slightly Included. Inclusions visible only under 10x magnification by trained graders.
- VS1, VS2 — Very Slightly Included. Most VS-grade diamonds are eye-clean.
- SI1, SI2 — Slightly Included. SI1 is often eye-clean. SI2 may have visible inclusions.
- I1, I2, I3 — Included. Inclusions visible to the naked eye. Generally avoided for fine jewellery.
The eye-clean sweet spot
A diamond is "eye-clean" when no inclusions are visible to the naked eye from a normal viewing distance. Most VS2 and many SI1 diamonds are eye-clean and offer outstanding value compared to chasing the highest clarity grades.
Where to compromise
For most buyers, the smart play is:
- Maximise cut — never below Very Good
- Optimise colour to your setting — F-H for white metal, H-J for yellow gold
- Find an eye-clean SI1 or VS2 — full visual quality at significant savings
- Maximise carat with the budget you save
This delivers a diamond that looks stunning at a substantial price advantage over chasing top grades.