Cut, Color, Clarity, Carat. Four letters that decide what a diamond costs — and what it actually looks like on a finger. Here's what matters, what doesn't, and where the industry quietly overcharges you.
01 — Cut
Nature grows the rough. A human decides how to cut it. Facet angles, symmetry, and polish are what make a stone sparkle — not carat weight and not clarity.
A well-cut G/VS2 will out-sparkle a poorly cut D/IF every single time. If you cut a single corner in the 4Cs, cut clarity or color — never cut on cut.
Rule: Excellent or Ideal cut only. Nothing below Very Good, ever.
Light Return by Cut Grade
Maximum brilliance. Precisely proportioned facets.
Near-ideal light return; small trade-offs invisible to the eye.
Some light leakage; still attractive at the right price.
Noticeable dullness; avoid unless heavily discounted.
Light escapes through the bottom. Skip.
02 — Color
The scale runs D (perfectly colorless) to Z (light yellow or brown). Fancy colors — blue, pink, green — sit on a different scale entirely.
Here's the industry secret: nobody can tell D from H face-up in a normal ring setting. The difference is only visible face-down against a white card, under controlled lighting, by a trained grader.
Rule: G or H in white gold and platinum. I or J in yellow gold — the metal warms the stone anyway.
Color Grade Scale (D → M)
03 — Clarity
Clarity measures inclusions — tiny mineral fingerprints locked in the stone. Grades run FL (flawless) down to I3. The catch: 95% of buyers can't spot the difference between VS1 and IF without a jeweler's loupe.
Anything VS2 and above is "eye-clean" in a well-cut stone. Paying for VVS or IF is paying for a certificate detail, not for what your eye can see.
Rule: VS1 or VS2 in brilliant cuts. Bump to VVS2 in emerald and asantillo cuts, where step-facets show inclusions more.
Grade Ladder
Interactive Tool
Move each slider to see the inclusion pattern and what the difference actually costs.
Minor inclusions, difficult to see under 10×.
The sweet spot. Eye-clean, meaningfully cheaper than VVS. This is where most experienced buyers land.
Inclusions easy to see under 10×; may be visible to the naked eye.
Real gamble without a video. A well-cut SI2 with inclusions hidden under the crown can be a steal; a poorly placed one is visibly flawed.
The Difference
VS1 sits 3 steps cleaner than SI2. For a well-cut 1.5ct round, expect roughly 36–66% price difference on identical color and carat — often invisible without a loupe.
04 — Carat
One carat is 0.2 grams. Two stones of identical carat can look dramatically different sizes depending on cut proportions — a deep-cut 1ct can appear smaller than a well-proportioned 0.9ct.
Prices jump sharply at "magic weights": 0.50, 0.70, 1.00, 1.50, 2.00. A 0.98ct is often 15–20% cheaper than a 1.00ct with nearly identical face-up size.
Rule: Shop just under magic weights. Prioritize millimeter diameter over carat weight.
Face-Up Size (Round Brilliant, mm diameter)
Doubling the carat doesn't double the face-up size — it grows by roughly 26%. Depth adds weight you'll never see.
Ready
Our AI applies every rule on this page automatically — ranking stones across 20+ certified retailers by true price-to-quality.
Search DiamondsFree. No account required.