SIZE AND BRILLIANCE

Between gem-quality diamonds of the same cutting style, the strength of brilliance will differ with size. When arranging small diamonds to bring out their beauty, the superiority or inferiority of a conception depends upon whether or not this fact is understood. When a smaller version of a popular piece of jewelry is made, only to become something totally lacking in beauty, it is because of a failure to consider the fact that the brilliance of diamonds changes with size. The brilliance of round brilliant cuts is drastically reduced in sizes under 2.0 millimeters, because the facets become too small to fully show the beauty of the light and dark tones of a mosaic pattern. In the case of marquise brilliant cuts, a stone of less than 3.5 x 1.7 millimeters cannot exhibit the type of beautiful brilliance achieved in one measuring 4 x 2 millimeters, no matter how excellent the rough material and the cut. Consumers often refer to very small diamonds as “diamond chips,” a term that aptly describes the fact that a 1-millimeter diamond’s brilliance does not compare to that of a 2-millimeter diamond.

At around 1.4 millimeters, single-cut diamonds with 18 facets are more strongly brilliant than the 58-facet full cuts. Comparing several single-cuts and full-cuts face-up under natural lighting, the brilliancy of the single-cuts is surprising. Superior jewelry uses full-cut and single-cut diamonds in the same piece according to their sizes, proof of the director’s knowledge, gained through experience, of the relationship between size, brilliance, and the diamond’s cutting styles.

All other conditions being equal, brilliance increases with size, and round brilliant cuts are most brilliant at two-carat sizes. This level of attractive brilliance cannot be achieved in larger sizes such as five or ten carats, because the well-balanced mosaic pattern, created by the facets due to internal reflection and refraction, is weaker. In Japan, 0.3-to 0.5-carat-size diamonds, with many extra facets are popular, but placing more than 58 facets on small stones often throws off the balance of brilliancy, and caution is necessary.

Emerald cuts of over 1.5-cafrat size fully exhibit a clear, lustrous brilliance. This strong brilliance that emanates from within, as seen in the channel-set diamond ring on page 67, is characteristic of step-cuts. Diamonds are gifts from nature: Even a single small diamond deserves to be put to its best possible use with an understanding of its character and beauty.