The Brilliant Cut

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

The meaning of the word Brilliant has changed over the years. Today the term is restricted to the modern, round, Brilliant Cut diamond with a table and thirty two other facets in the crown, a culet and twenty four facets in the pavilion. Back in 1564 the name began in France to replace the term Mirroring. At first it was used adjectivally but from 1608 it occurred occasionally as a noun, though not then indicating any specific type of faceting. In the Crown inventory of 1691, drawn up for Louis XIV, it was used exclusively for Brilliant Cuts—except for three separate examples of other cuts with exceptional light effects, which were also described as Brilliants.

The 1691 inventory is particularly reliable because it was compiled with great care and accuracy by professionals. The various cuts were described by Louis Alvarez, a famous diamond expert, and by Pierre Montarsis, the leading Paris jeweler. The entries were also checked and supplemented in great detail by the king himself, assisted by his secretary and Minister of Finance, Pontchartrain. Two examples are of interest. The French blue diamond is described as ‘à facettes à la mode des deux côtés, coeur court à 8 pans’. The description of the stone having eight main facets is strange when we know that the symmetry was sevenfold; they must have included the table. The fact that the gem was Stellar Cut is not mentioned. The first diamond of an agraffe is described thus: ‘Fort, haut de forme, carré, à la monde, grande étendue, 42⅝ ct.’ In later inventories all these diamonds are described simply as Brilliants. By the beginning of the eighteenth century the Brilliant Cut was well established, but the term itself still embraced other cuts, including not only all the modified Brilliant Cuts but also Sancy’s and Briolettes.

The true history of the Brilliant Cut is far more interesting than the stories which simply attribute its creation to various inventors. The earliest Brilliants were fashioned from several obsolete diamond cuts such as Burgundian Point Cuts, Pointed Star Cuts and Tailles en Seize, all of which were once developed from dodecahedral rough. The squarish shapes, which appeared later, were either fashioned from octahedron or, at least to begin with, were recuts of old High Table Cuts.

The old cuts no longer appealed. People wanted diamonds that would sparkle in the candlelight at the now fashionable night parties. A new pavilion-based cut was needed to complement the flat-bottomed Rose Cuts, whose popularity grew rapidly in the second half of the seventeenth century. And it was essential to make the best use of crystals that were well developed.

The creators of the initial ‘round’ Brilliant met with no real problems in designing its faceting. After having applied a table, surviving diamonds served as models; the Sancy Cuts for the crown part and the Pointed Star Cut for the pavilion. Thus, starting from any available round Point Cut with its apex first removed, they arrived easily at a prototype of a Brilliant Cut. If the basis for the experiment was a Pointed Star Cut, which is likely, the facetings alone called for a retouch.