The Côte de Bretagne is a 107.88-carat red spinel, carved into the form of a dragon, that is one of the few surviving members of the French crown jewels and is now held at the Galerie d'Apollon of the Musée du Louvre in Paris. It is among the oldest pieces in the surviving French regalia and predates the great seventeenth-century purchases of Cardinal Mazarin and Louis XIV; its history can be traced through the French royal treasury for some five hundred years. The stone is doubly significant: as a great historical gem in its own right, and as a marker of the older confusion in which red spinel and ruby were not gemmologically distinguished, since the Côte de Bretagne was for centuries described as a balas ruby (balais or spinelle being later refinements of the same red-stone category).

Origin and the Anne of Brittany attribution

The traditional account holds that the stone entered the French royal collection through Anne of Brittany (1477-1514), Duchess of Brittany and twice Queen of France through her successive marriages to Charles VIII and Louis XII. The stone is named for her in this account: the Côte referring perhaps to its dragon-shaped engraving, perhaps to the form of the original rough crystal, and de Bretagne to her duchy. Anne is recorded as having brought a substantial inventory of jewels with her into the French royal treasury at the time of her marriages, and the Côte de Bretagne is among the pieces traditionally identified with her. The earliest documented French royal references to the stone date to the sixteenth century, in inventories of the crown jewels under Henri II and his successors.

The Jacquemin engraving

The most striking feature of the Côte de Bretagne is its carved form. In 1749, by command of Louis XV, the stone was engraved by the lapidary Jacques Guay (also recorded under the spelling Jacquemin in some sources, with the work sometimes attributed to him directly) into the form of a dragon, intended to be set as the dragon component of the insignia of the Order of the Golden Fleece. The carving reduced the stone's weight from a previously documented figure of approximately 206 carats to its present 107.88 carats, a striking sacrifice of weight for the sake of an emblematic form. The dragon, in the iconography of the Order, was wrapped around or supporting the Golden Fleece itself, with the spinel forming the body of the creature and additional gems (notably a large diamond, the Bazu, and other stones) forming surrounding elements.

The 1792 theft and recovery

The French crown jewels were stolen in September 1792 from the Garde-Meuble (the royal storehouse) on the place de la Concorde in Paris, in one of the most spectacular thefts of European history. Most of the stolen pieces were dispersed irretrievably, with the great French Blue diamond reappearing only later as the recut Hope diamond in London. The Côte de Bretagne, however, was among the relatively small number of pieces recovered, having been hidden by one of the thieves in a beam of the building. It was returned to the French state and remained in the official collection through the Restoration, the Second Empire, and the Third Republic, surviving the 1887 sale of much of the remaining French crown jewels under the early Third Republic when the state liquidated most of the regalia.

Present status

The Côte de Bretagne survived the 1887 sale because it was classified - along with the Regent diamond and a small number of other pieces - as a historical and artistic object too significant to be sold. It is now displayed in the Galerie d'Apollon at the Louvre as part of the surviving French crown jewels collection, alongside the Regent and the Sancy. Modern gemmological analysis has confirmed the stone's identity as red spinel rather than ruby - a determination that the eighteenth- and nineteenth-century lapidaries could not have made with certainty. The stone is a particularly fine example of Burmese (Mogok) spinel, with a saturated red colour that runs slightly lighter than the deepest "pigeon-blood" rubies of the same source and a clarity that even after carving remains exceptional.

Significance

The Côte de Bretagne occupies a place in the gemmological canon at the intersection of three histories: the history of the French monarchy, with its specific connection to Anne of Brittany and the long French royal regalia tradition; the history of the conflation between ruby and red spinel, which the stone shares with the Black Prince's Ruby in the British Crown Jewels and the Timur Ruby; and the history of gem engraving, since the dragon carving is one of the most ambitious surviving examples of large-scale gem engraving from the eighteenth century. Together these histories make the stone, despite its relatively modest size by Mogul or Mughal standards, one of the more significant individual gems in the European tradition.