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Diamond Proportions

Proportions Charts

FirescopeHearts & Arrows Ideal Cut

This cut displays the visual phenomenon that appears in the world's finest, ideal, round brilliant cut diamonds. A Hearts & Arrows Ideal Cut Diamond is the ultimate, most magnificent cut diamond man can produce; it accounts for less than 1% of all diamonds cut. The highest grades of polish and symmetry allows it to reflect more light than the standard American ideal cut.

The phenomenon of the Hearts & Arrows Ideal Cut may be viewed easily by anybody that possesses a proportion or fire scope.

Arrows displayed in diamond under firescope Hearts displayed in diamond under firescope Arrows displayed in diamond under firescope Hearts displayed in diamond under firescope

57% Table Ideal CutAmerican Ideal Cut

This refers to approximately 16% of the top diamond quality based on cut. The range for the proportions as defined by the American Gem Society: Table Diameter: 52.4% to 57.5%, Crown Angle: 33.7 to 35.8, Girdle Thickness: Thin to Slightly Thick (.51% to 2.95%), Pavilion depth percentage: 42.2 % to 43.8%, Culet: (Pointed) None, Very small to Medium and Total Depth: 58.7% to 62.3%. Noting good symmetry and polish. These percentage ranges justify the beauty and quality of the diamond. An Ideal American cut will reflect nearly all light and is truly a top quality, striking and highly prized cut.

AGS Ideal Cut Proportions

63% Table Fine CutInternational Fine Trade Cut

This refers to approximately 24% of the top diamond quality based on cut. International Fine Trade cut or "Fine Cut "is still within the range of a well cut diamond, it will reflect most light that enters it and has a healthy beauty. The benefit here starts to become noticeable with price.

Compare Ideal vs Standard Manufacturing

Average CutAmerican Average Cut or Average Cut

Corresponds to approximately 38% of the usual diamond quality based on cut. Average cut diamonds are more usual commercial cut trade heavily in the bulk of mass produced jewellery. These diamonds are usually cut for weight. An Average cut diamond will reflect light and is sparkly.

Below Average CutBelow Average Cut

Corresponds to all the rest of round brilliant shaped diamonds that fall outside normal specific cutting ranges. These diamonds are too deep, narrow, shallow or wide and lose most of their brilliance and fire. The light passes through and leaks out of the stone. Some of these stones may have an interest and beauty factor, price should be well below that of superior diamonds.

Marcel Tolkowsky

Marcel Tolkowsky was a Belgian diamond cutter who in 1919 publicised his determinations for the most attractive and balanced cut for round brilliant diamonds. His proportions were based on experience, maximum beauty, collected opinion and mathematical calculation. The results set the industry standard for many years. Marcel could be described as the father of the modern brilliant cut.

Tolkowsky Diamond

His proportions for cutting were followed and approximated for many years.

Diamonds are sometimes improperly called Tolkowsky cuts when their proportions range only approximates that of the exact proportions determined by Tolkowsky.

These proportions are

  • 34.5 Crown Angle.
  • 40.75 Pavilion Angles.
  • 59.3% Total Depth (excluding girdle thickness) with 16.2% of the depth being comprised of the crown (top half of the diamond) and 43.1% representing the pavilion lower half of the diamond.
  • 53% Table based on diamond's overall diameter.

Now with increased desire for perfection and with greater beauty the Hearts and Arrows Ideal Cut Diamond was created to even more exacting proportions of balance and beauty, remembering that only an exact, small changeable ratio of proportions creates this phenomenon of the Hearts and Arrows effect.