ON IMPROVING THE CUTTING BY
By Joe C. C. Yuan-- G.G., D.G.A.
The author's note: Nowadays consumers know how to judge the purity and color of diamonds, but they are clueless about the quality of the cutting. In fact, the brilliance of the diamond is closely related to the cutting. A new cutting style has been adopted after the ideal cutting has been popular for a century, and the primary purpose is to maximize the brilliance of diamonds.
The round brilliant consists of about 95% of the cutting style of diamonds. There have been little changes in the cutting style of round-shaped diamonds over the past hundred years. The discovery of the round brilliant cutting has by now reached its hundredth year. Its original cutting style was to cut a rough in the shape of octahedra or dedacahedra into a diamond with a small table, steep crown angle, very large culet and short lower girdle facet (Fig. 5-1). Following the use of electric saws in cutting of diamonds, a octaheral or dedahedral diamond could be cut into two halves. With the introduction of ideal cutting in 1919, a very small number of diamonds were cut with the ideal cutting as shown by Fig. 5-2--with 53% table, 34 1/2o crown angle and 40 3/4o pavilion angle. Most of the diamonds were cut with modern cutting as shone in Fig. 5-3 with 58-65% table, 30-36o crown angle and a 41-43o pavilion angle. In the past seventy-odd years there have been little new changes. As far as the diamonds available on the market are concerned, the only change is to increase the height of the lower girdle facet.
Variants of the Round Brilliant Cutting Style
Many people have attempted to improve upon the round brilliant cutting style in the past century. One instance is the 144-faceted cutting (Fig. 5-4) that came about thirty years. This style is featured by adding 48-facet close to the girdle at the bottom, but as they are too close to the girdle, the reflection is not noticeably enhanced when viewed from the top. Several years ago Basil Watermeyer (the inventor of Barion rectangle, crown step cut and brilliant bottom) added a facet to each lower girdle facet close to the girdle at the bottom, as is shown by Fig. 5-5. Its purpose was only reduce the fisheye effect in thin diamonds. In addition, the crown and bottom has been increased from eight sectors to ten sectors. Every star facet on the crown is vertically divided into two, and every kite facet is horizontally divided into two. Owing to the unsatisfactory effect, they were not accepted by the market.
Solstar™ -- New Round Brilliant Cutting
In the course of his many years experience in diamond cutting, the author feels that the ideal cutting, as shown in Fig. 5-2, produces good brilliance but causes much loss of weight in the rough. Diamonds with round brilliant cutting, as is shown in Fig. 5-3, are heavily favored in the market today, but their brilliance is less than ideal. The center part of the diamond is lacking in brilliance and unimpressive. Because of this, the author has been experimenting with different ways to improve the cutting to enhance the brilliance of diamonds. The following ways are all featured by increasing facets on the bottom and adding one or two more layer of pavilion facets. If directly applied to the rough, it adds 1-3% of weight recovery to the polished diamond, as is shown in Fig. 5-6. When the depth of the bottom is the same, more weight can be retained in the lower one of the two layers of pavilion facets. Solstar™ cut family with 168, 128, 66 and from 73 to 82 with every specific number. If recut from 57-faceted or 58-faceted standard cutting, the weight lost is mostly less than 1%, and sometimes it is even less than 0.5% to 0.1% . The effect of the Solstar™ cut is most clearly reflected in the obviously enhanced scintillation and brilliance, as is shown by Fig. 5-7 to 5-18. If the bottom is steep in the original cutting, the improvement is seen in the increased reflection.
If the original cutting is flawed, it can be improved upon with different cutting methods for better effect.
If the diamond has good original cutting, it can be changed into any one of the new cutting, with enhanced effect of beauty. The cutting with many facets is suited for larger diamonds as a small diamond with too many facets has too many light spots, thus appearing to be scrappy.
Solstar™ cut also is good on fancy shape, such as heart, marquise, pear, radium and princess to improve their brilliance. Solstar™ cut will increase clarity scillation, life and improve color on top view with naked eyes.
The Solstar™ cut will increase clarity scillation, life and improve color on top view with naked eyes. The Solstar™ cut will conserve the weight of diamonds when they are used on the rough and cause less loss of weight when used to recut polished diamonds. And they yield more brilliance than the traditional cutting.