Diamond Education

The 4 Cs, explained.

Every diamond is graded on four independent qualities: cut, color, clarity, and carat. Here's what each one actually means for how a diamond looks — and where the real value is.

Cut Color Clarity Carat

Cut

Cut measures how well a diamond's proportions, symmetry, and polish work together to reflect light. It's the single biggest factor in how much a diamond sparkles — and unlike color or clarity, a poor cut can't be corrected by a better grade elsewhere.

Poor

Fair

Good

Very Good

Excellent

Recommended: Excellent — never worth compromising on cut

A note on fancy shapes

This scale applies to round brilliant diamonds — the only shape GIA assigns an overall cut grade to. Oval, cushion, emerald, and other fancy shapes are graded on polish and symmetry instead, so look for Excellent in both when choosing a fancy-shape diamond.

Oval

Cushion

Emerald

Color

Color measures how much natural yellow or brown tint is present — graded from D (completely colorless) to Z (visibly tinted). The less color, the more light passes through cleanly.

D–F
Colorless

G–H
Near-colorless

I–J
Faint warmth

K+
Noticeable tint

Sweet spot: G–H — reads as white face-up, without the D–F premium

Why G–H is the smart default

Once a diamond is set — especially in white gold or platinum — most people can't distinguish a G or H color grade from a D. You're paying a steep premium for a difference that's really only visible loose, side-by-side, under a jeweler's light.

Clarity

Clarity measures internal inclusions and external blemishes — natural characteristics formed as the diamond grew. Almost every diamond has them; what matters is whether they're visible to the naked eye.

FL–IF

VVS1–VVS2

VS1–SI1

SI2

I1–I3

Sweet spot: VS2–SI1 — "eye-clean," with no inclusions visible unaided

Flawless is for collectors, not sparkle

Flawless (FL) and Internally Flawless (IF) diamonds are graded under 10x magnification most people will never use. A well-chosen VS2 or SI1 diamond looks identical to the naked eye at a fraction of the price.

Carat

Carat measures weight, not size — one carat equals 0.2 grams. It's the only one of the 4 Cs that isn't a quality grade, and it's where buyers most often overpay without realizing it.

0.50ct ~5.2mm

1.00ct ~6.4mm

1.50ct ~7.3mm

2.00ct ~8.1mm

Why price jumps at round numbers

Rough diamonds large enough to cut into a full 1.00ct or 1.50ct stone are disproportionately rare, so price per carat jumps sharply at those thresholds — not gradually. A diamond just under the line, like 0.90ct or 1.90ct, often looks the same size once set and can cost meaningfully less.

One more thing worth knowing: carat measures weight, not visual size. Elongated shapes like oval and emerald spread their weight across more surface area, so they can appear larger than a round diamond of the same carat weight.

Ready to see it for yourself

Every Carat Compass diamond is graded before it's ever listed.

GIA or IGI certified, sourced directly, and priced without a showroom markup.

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