The cut of a diamond is a major factor in determining its value. Cut is one of the four c’s that work together to determine a diamond’s value. Diamond cutting is the process that creates a gem-quality diamond out of mined rough materials. A diamond’s cut describes the way a diamond has been shaped and polished from its beginning form as a rough stone to its final gem proportions. The diamond’s cut also describes the quality of workmanship and the angles to which a diamond is cut. The cut of the diamond is often confused with the shape, but the cut primarily determines its shape. Experts use mathematical guidelines to determine the angles and length ratios at which a diamond should be cut to reflect its maximum amount of light.

The round brilliant cut is the most common diamond cut. The brilliant cut is guided by specific mathematical guidelines, but fancy cut stones are not able to be accurately guided by mathematical guidelines. The techniques for cutting diamonds have been crafted and perfected over hundreds of years. Mathematician Marcel Tolkowsky made the greatest achievement in diamond cutting in 1919. Tolkwosky created the round brilliant cut by calculating the ideal shape to return and scatter light when a diamond is viewed from above.

Today, the round brilliant cut has 57 facets (polished faces) with 33 on the crown(top half of diamond), and 24 on the pavilion(the lower half). The crown diffuses light into various colors, and the pavilion reflects light back through the top of the diamond. The further a diamond’s characteristics are from the Tolkowsky’s ideal cut diamond, the less light that will be reflected by the diamond. However, today, carat weight tends to be more important than a diamond’s cut, so many diamonds are cut poorly to increase the carat weight. In cutting the diamond the middle is known as the girdle, and the girdle is often made thicker or the depth may be increased to make the carat weight closer to 1.0 carat. Increasing the depth of the girdle does not make the diamond appear bigger, and it greatly reduces the sparkle of the diamond. 

A poorly cut 1.0-carat diamond may have the same diameter and appear as large as a 0.85-carat diamond. The depth percentage is the first indication of the quality of the cut of a round brilliant diamond. An ideal round brilliant diamond will have a depth percentage greater than 62.5 percent. Another indication of a quality cut will be the diamond’s overall diameter. A round brilliant cut 1.0-carat diamond should have a diameter of 6.5mm. The Gemological Institute of America has surpassed Tolkowsky’s mathematical model with its Facetware software, which is the culmination of 20 years of studies on diamond cuts. In 2003, the Genesis cut was developed; the cut differs in shape from the traditional cuts. The Genesis cut has concave surfaces and angles and resembles a four-pointed star.   

Diamonds could be cut square round, oval, and other shapes, and all diamonds are put into three main categories, which are brilliant cuts, step cuts, and mixed cuts. Brilliant cuts have many facets, shaped like triangles that point outward, allowing light to be captured and shine through the diamond. In brilliant cuts the light bounces off of the facets and creating a brilliant shimmer to the stone. Step cuts have fewer facets than brilliant cut diamonds, and its facets are sloped with four sides that step up and down on the slope of the cut. The emerald cut is the most common step cut, which is cut into a rectangular shape. Mixed cuts are a mix of between brilliant and step cut diamonds. The part of the diamond viewed from the top will be a step cut, with the under side being a brilliant cut.

Trackback URI | Comments RSS