The Three Brethren

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

The most striking example of a fashioned trisoctahedral design is the 30ct diamond point in the center of the jewel known as The Three Brethren which was dismantled and dispersed c.1642. In the rough this diamond probably had distinctly rounded faces, a shape often found in India. Its fame rests on three factors: the giant, well-matched and extremely rare red spinels which gave it its name; the four huge Oriental pearls, and the magnificent diamond, whose beauty, strangely enough, only gradually came to be fully appreciated. It was only in 1623 that James I’s jeweler, Heriot, commended it as the most ‘compleat’ stone that he ever saw.

From a thorough study of all available material I was able to construct a replica and to determine the following facts: the diamond was bipyramidal and weighed about 30 ct or slightly more, and its outline was almost that of a regular square, with an average width of about 16 mm. Based on these figures, the overall height could be calculated to about 128 percent, and angles of inclination to an average figure of about 52º (the corresponding figures for a regular octahedron are 141.42 percent and about 54¾º). These proportions can be confirmed by the relative size of the reflection.

As to the faceting, the descriptions clearly indicate a cut that was an imitation of a regular trisoctahedron. The illustrations neither confirm not contradict this but indicate only that the main facet edges were ground down to very narrow facets. Charles the Bold’s inventory of 1467 states that the gem was ‘un gros dyamant pointy a fass’ (i.e. faceted). Fugger’s sales document of 1504-5 says ‘ein demandtpundt indermitt gefieri.’ The word gefiert here means ‘divided into four sections’. This was interpreted by Kind in 1867 and by Streeter in 1882 as ‘having the apex cut into a four-rayed star in relief, each ray corresponding with the center of each face of the pyramid.’ Certainly no possible alternative has been suggested for this early gem.

The reason why the details of the cut cannot be detected from any of the illustrations is partly because the setting is very heavy and hides the lower part of the faceting, and partly because the diamond is always shown only from directly above, which distorts the design. In the drawing by Fugger, which is carefully executed, the ‘shadow’ of the reflections also disguises the top part of the faceting.

Most art historians agree that the jewel was created during the first decade of the fifteenth century. Early documents, however, do not mention The Three Brethren before the murder of Duke John the Fearless of Burgundy in 1419. The first mention dates from the time of the pawning of Duke John’s old plate and jewels in 1412. The Recette Generale in the Lille archives includes among the pawned objects ’22 large pearls, 2 square balaxes in a gold setting....and 1 large square pointed diamond in a gold setting, the which dyamond is the size of a filbert nut’. At that period the Dukes of Burgundy resided in Paris, so it may be assumed that the diamond was acquired in that city, if not necessarily fashioned there. However, diamond cutters were working in Paris around the turn of the century, and it is most likely that both bruting and accurate faceting on a scaife had been fully mastered at least by 1400. Well-shaped octahedrons and large diamonds in general were not normally available on the European market, so the rough stone probably had the shape of an irregular rounded crystal. This would first have to be bruted by hand, a tedious operation but one which would transform the crystal into a slightly rounded double pyramid on whose curved faces it was far easier for the cutter to apply ‘trisoctahedral’ facets than to achieve smooth and shiny large facets.