The shape library
The shape of a decision.
Explore eleven diamond shapes, then compare millimetre dimensions and approximate carat weights in each shape’s size chart.
Brilliant cut
Round brilliant
Balanced. Luminous. Versatile.
A circular outline and a radial facet arrangement create an even play of light. The round brilliant is a familiar starting point for solitaire settings and matched layouts.
View round brilliant size chart A closer look at round brilliantIllustrative faceted models, shown under consistent lighting. Actual stones, facet patterns and proportions vary.
A sense of scale
Round brilliant
size chart.
All sizes, in two parts. Select any weight below to compare its approximate millimetre size.
Measured across the circular outline, viewed from above.
Understand carat and the 4Cs01 Small stones
0.02–0.20 ct
| Carat weight (ct) | Diameter (mm, approx.) |
|---|---|
| 1.7 | |
| 2 | |
| 2.2 | |
| 2.4 | |
| 2.5 | |
| 2.7 | |
| 2.75 | |
| 2.8 | |
| 3 | |
| 3.2 | |
| 3.4 | |
| 3.7 | |
| 3.8 |
02 Larger stones
0.25–5.00 ct
| Carat weight (ct) | Diameter (mm, approx.) |
|---|---|
| 4.1 | |
| 5.2 | |
| 5.8 | |
| 6.5 | |
| 7.4 | |
| 8.2 | |
| 9.4 | |
| 10.4 | |
| 11.2 |
† Calculated estimate from nearby published sizes. Below the smallest reference, dimensions are scaled assuming unchanged proportions. These entries describe an illustrative size, not a measured stone.
Educational estimates. Carat measures weight: 1 ct = 0.2 g. Depth, girdle and proportions affect dimensions, so there is no exact mm-to-carat conversion. Check the individual stone’s measurements and grading report.
References: Diamond Source of Virginia size chart · Palloys small-diamond chart (PDF, p. 140)GIA carat education
Build a useful brief
More than
a carat weight.
Shape, millimetre dimensions, colour, clarity and matching requirements help define what you need. For individually reported stones, specify your preferred laboratory and documentation.
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a simple brief.
Add the specifications you know, or describe the requirement in your own words. Availability and documentation are confirmed directly by our team.
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