Marie Antoinette's tiara contained a ruby, a sapphire, an emerald, and a diamond until she had it dismantled.
King Louis XVI gave Marie Antoinette a tiara for one of her birthdays which contained a ruby, a sapphire, an emerald and a diamond. It was so extravagant that she refused to wear it, calling it her crown of ruination, as the French public was starving and it presented her as apathetic towards them. Marie had the tiara dismantled, with the ruby, sapphire and emerald placed into medallions. She then hid the "diamond of misery" in a contraption beneath the tower she frequented in Chateau Rochemont, with the medallions used as keys to access it. She wanted the jewels to be returned to the people of France where they belonged, but she knew it couldn't happen until the country had healed from the tumultuous revolution it was undergoing.
Marie sent the emerald medallion to her cousin Helga in Austria, while she hid the other medallions and her journal in a secret compartment in the tower. When fleeing the angry rebellious citizens of France, Marie and the King were advised to take jewels in case they needed to bribe for their escape, so she took the ruby medallion with her. However, they were still captured by Jean Le Bouef on June 25, 1791 and everything Marie had was taken, including the tower, which Le Bouef attached to his library.
In the 1920s, Ezra Wickford bought the tower and library and had them attached to Wickford Castle in Butter Ridge, Wisconsin. One of the carpenters dismantling the tower, the great grandfather of Jacques Brunais, discovered the secret compartment and kept the sapphire medallion, but didn't have time to take the journal before other carpenters arrived. Ezra discovered the ruby medallion in the library, most likely in the secret room, and left it in the garden as a "good luck charm" for his son Dexter, as well as clues as to how to find it in the secret room; however, Dexter never found the room, leaving it for Nancy to find in 2001 in Treasure in the Royal Tower. Jacques had come to the castle with the sapphire medallion, hoping to get into the tower, and the emerald medallion had made its way down to the Baroness Helga von Hanseldorf, who became friends with Professor Hotchkiss. Knowing she was going to Wickford Castle, she gave Hotchkiss the medallion and all of them ended up at the castle. Nancy was able to use them and the Queen's journal, which she found in the tower, to find the diamond. All four jewels and the journal were then put in a museum in France.