The lead cast of the "French Blue", itself, has a history. It had been catalogued at the French museum in 1850 and was provided by a prominent Parisian jeweler named Charles Archard who lived during the same generation as René Just Haüy, who died in 1822. Most likely, the lead cast was made near 1815, since that was the year that similar entries from the 1850 catalogue had been made. The model was accompanied by a label stating that the "French Blue" was in the possession of a person known as "Mr. Hope of London". Other archives at the Muséum suggests that Achard had Mr. Hope as a good customer for many long years, particularly for blue gems.