Round Brilliants

(via Diamond Cuts in Historic Jewelry:1381-1910) Herbert Tillander writes:

From the time the Brilliant Cut was introduced, round Brilliants have been fashioned, but never—at least until recently—in any quantity. The tedious process of manual bruting and the loss of weight and size made them economical. Perfect circular outlines were extremely rare, even though they appear in the illustrations of Jeffries, Caire and a great many others who have obviously symmetrized their line drawings. In fact, the only type of crystal that can be easily rounded is the extremely rare regular dodecaheron.

No historical analysis of the round Brilliant Cut has ever been published and very little documentation is available. One might expect to find some interesting highlights in Mawe’s Treatise on Diamond (first published in 1813), but this contains more contradictions than information on styles of fashioning.

In the seventeenth and eighteenth centuries circular brilliants were considered Fancy Cuts and classified with Drop Shapes, Marquises, Hearts and so on. The standard outlines then in fashion were so strongly dominant that contemporary authors concentrated almost exclusively on them. Jeffries, for instance, in his Treatise of 1750, stated that the square Brilliant (derived from octahedral rough) was the standard, and describes only one circular, one oval and one drop-shaped Brilliant. He gives no examples of stones with any other outline, not even a cushion shape.

As late as 1858 the French writer, Barbot, disapproved of the circular outline because he claimed that stones of this shape display less attractive brilliance: ‘Le brilliant est généralmement carré arrondi. Nous avons cependant vu de très beaux brilliants, taillés nouvellement, entièrement ronds, mais cette forme, quoique jouer le diamant, lui donne un miroirement moins préférable, á notre sens, que la gravité sevère de la forme carrée arrondie.’

Many of the small Brilliants used in minor Victorian jewels have survived whereas the larger and finer gems were, for the most part, recut into modern round brilliants and transferred to new settings. With diamonds weighing ½ ct or more the cost of labor was negligible. The London Cut was easily recognizable and much in demand, so the English cutters concentrated on refashioning the larger stones, reshaping the square and cushion-shaped gems and replacing the old fourfold symmetry with something closer to eightfold in an attempt to reduce the leakage of light through the pavilion facets.

Small circular diamonds were needed to complement these large circular stones, and here the less strict Amsterdam cutters came into their own. They paid their workmen low wages and were soon able to flood the market with not very well made, but far cheaper, stones. By the middle of the nineteenth century the English master cutters were no longer able to compete with the large cutting centers on the Continent, but by then the circular Brilliant was well established in Europe and few decades later was introduced by Morse into the United States.