Diamond Buying Guide
Understanding diamond proportions is key to finding a stone with maximum brilliance, fire, and sparkle. Below are the ideal specifications we recommend for each shape.
The “Super Ideal” Round Brilliant
For a round diamond, the interaction between angles is more important than any single percentage. These specs represent the “sweet spot” for maximum light return:
Ideal Specs for Fancy Shapes
Because fancy shapes are judged visually, these ranges are used to find stones that “face up” large and avoid light leakage or “bow-tie” shadows.
| Shape | Table % | Depth % | Ideal L/W Ratio | Notes |
|---|---|---|---|---|
| Princess | 63% – 70% | 67% – 76% | 1.00 – 1.05 | Avoid table % higher than depth % |
| Cushion | 56% – 63% | 58% – 66% | 1.00 – 1.05 | Also look for 1.10–1.20 (Elongated) |
| Oval | 54% – 58% | 62% – 66% | 1.35 – 1.50 | Watch for the dark “bow-tie” effect |
| Emerald | 61% – 68% | 60% – 65% | 1.35 – 1.50 | Prioritize clarity (VS2+) due to step-cuts |
| Pear | 57% – 62% | 58% – 64% | 1.45 – 1.75 | Ensure symmetry on the rounded end |
| Radiant | 60% – 69% | 59% – 68% | 1.25 – 1.40 | Great for masking color in lower grades |
| Asscher | 59% – 65% | 60% – 68% | 1.00 – 1.04 | Step-cut like Emerald; prioritize clarity |
Quick Tips
Cut is King
A well-cut diamond will look larger, brighter, and more brilliant than a poorly cut stone of the same carat weight. Never compromise on cut quality.
Color vs. Clarity
For brilliant cuts (Round, Oval, Cushion), you can go lower on clarity (VS2–SI1) since facets hide inclusions. For step-cuts (Emerald, Asscher), prioritize clarity (VS2+).
Lab vs. Natural
Lab-grown diamonds are chemically, physically, and optically identical to mined diamonds — at a fraction of the cost. The same ideal specs apply to both.
Ready to find your perfect stone?
Browse our curated inventory of over 2 million natural and lab-grown diamonds — filtered to these ideal specs by default.