It was reworked and enriched (especially the bracelets) for the Princess to wear at the Coronation of her uncle Charles X in 1825.
Unlike most of the Crown Jewels, it was left untouched from 1825 to the end of the Second Empire and the dispersion of the jewels in 1887.
In 1887, the parure was composed of a diadem, a coronet (without arches), a large necklace, a small necklace, a large belt, a pair of bracelets, a pair of earrings, a pendant, two brooches, a "rosette" clasp and 14 corsage buttons.
In anticipation of the 1887 sale, a selection of the most important jewels was photographed by Berthaud, at the request of the major jewellery houses who planned to bid on certain pieces.
Plate 12 shows both necklaces, bracelets and the brooch-pendant.
Plate 14 shows the diadem and coronet
Plate 15 shows the front section of the belt, earrings and small shoulder brooches
Berthaud illustrated catalogue is available on Gallica-Bnf: https://gallica.bnf.fr/ark:/12148/btv1b10525652m.r=berthaud?rk=128756;0
To my dismay, the only elements from the Parure in the Louvre are the pair of bracelets.
In 1887, the bracelets were sold to Tiffany's.
The diadem and bracelets were acquired by Cornelia Bradley-Martin, who left them to her only daughter Cornelia, Countess of Craven, who sold them at Sotheby's in 1961.
The bracelets were in turn acquired by S.J. Phillips, the London jeweller, from whom Claude Menier bought them. He generously willed them to the Louvre in 1973.
Cornelia Bradley-Martin wore the bracelets as a choker as part of her "Mary Stuart" costume at the Bradley-Martin Ball, 1897.
She wore other pieces from the Crown Jewels on that occasion, as well as her own diamond tiara.
The last time the Diadem was shown in the Louvre was in 1962:
It is reportedly preserved in a private collection (Niarchos?).
Minor pieces, mostly elements from the belt, have resurfaced over the years, often modified, but the most important element sold in recent years was indeed the great necklace.
In 1887, both necklaces were acquired by Monsieur Bapst (Germain?). Paul Alfred Bapst (1823-1879) was indeed the last Crown jeweller. Germain Bapst had a great appreciation for the historic value of the stones and mounts. It seems likely the necklace remained with him or the Bapst family until the 1920s, when it may well have been sold to Sir George Cooper (whom I don't know anything about), possibly through Carrington.
However, a few questions remain.
In Berthaud's lithographs, the necklace is shown "sans" pendant, perhaps to allow it to fit on the photographer's plate.
Other contemporary photos show a pendant of similar design to the other pendants on the necklace, and to that of the necklace sold in 1982.
As Beth explained, the necklace was apparently sold twice at Christie's Geneva:
The first time on 2 December 1982, with pendant and modern earrings (commissioned from Van Cleef & Arpels in 1951) matching the other elements,
The second time on 27 May 1993, with a different, pear shaped, pendant.
Bernard Morel, writing in 1988, considers the longer necklace was slightly modified at a later date with the central pendant and clasp replaced.
Personally, I wonder if the necklace hasn’t be entirely reworked sometime between 1887 and 1982. Indeed, in recent photographs, it is clear the distinctive "claws" used in the setting of the smaller rubies have disappeared. The same goes for the bigger rubies, whose light setting have also been replaced by continuous, thicker, gold borders.
Comparison 1993 – 1887
Maybe the stones have been reset to consolidate the whole mount. However, the brooch-pendant sold in the 1990s as well still displayed the typical "claws".
I believe this is the Auction lot notice, though I can't find a date for the sale.
The clasp in the form of a rosace was sold by Sotheby's London, on 16 December 2004.
The coronet, small necklace, earrings, shoulder brooches, buttons and most of the belt are unaccounted for.
To this day, the glorious Ruby Parure, although dispersed and altered, is probably the best preserved ensemble from the former French Crown Jewels.
[Sources: Bernard Morel, Les Joyaux de la Couronne de France, 1988 ; Vincent Meylan, Christie's, The Jewellery Archives revealed, 2016 ; Musée du Louvre ; Sotheby's, Christie's]