How Diamonds Are Polished

Processes to transform a diamond in the rough into the exquisite brilliant of commerce

polishing diamond

The actual cutting of the facets on the diamond, known as “polishing,” calls for the highest expression of the diamond lapidary's art. The stems of the “dop,” which bear the diamonds, must be adjusted in the “tongs” with fine nicety. Here again the form of the tools has not changed in a century. The iron “tongs,” the wheel and its spindle (shown in the center of this picture), even the metal pegs against which the tongs are kept in place on the wheel, are the same as those used in Amsterdam and Antwerp in 1821.

This gave eight facets grouped about the table and eight below the "girdle," as the line encircling the stone at the point of the setting is called. At a previous stage in its development a small facet called the "culet," directly opposite the table, had been introduced, so that we have for this cutting, which has sometimes been called the single-cut brilliant, a total of eighteen facets. This gave eight facets grouped about the table and eight below the "girdle," as the line encircling the stone at the point of the setting is called. At a previous stage in its development a small facet called the "culet," directly opposite the table, had been introduced, so that we have for this cutting, which has sometimes been called the single-cut brilliant, a total of eighteen facets.

Up to this point in the development of diamond cutting, stones were cut for symmetry of outline alone and no attempt was made to utilize the remarkable optical properties of the diamond, which enable it, when properly proportioned in the cutting, to reflect back to the eye most of the light which falls upon it. Toward the close of the seventeenth century Vincenzio Peruzzi, a Venetian, began to cut diamonds on this principle. With this discovery, no longer the lapidary labored solely to produce a maximum weight and symmetry of outline, but he endeavored to combine with these the very essential factor of the brilliancy of the stone. And with increased skill in the art, more facets were added to beautify the form and enhance the radiance of the gem. Sixteen additional “corner facets” above and sixteen below the girdle rendered it rounder and more symmetrical, and subsequently eight extra facets grouped about the table completed the fifty-eight of the modern brilliant.

It is a singular and somewhat significant fact that the historical evolution of the modern brilliant as here traced is precisely its actual evolution under the hands of the diamond cutter. The facets are added to the stone in just the order in which they were developed through the centuries.

 

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