During the Universal Exposition at Paris, in 1855, the jewels of the Crown were displayed to the public. Many of the gems were mounted for the occasion in new parures; and the arrangement presented one of the most charming exhibitions ever seen in civilized countries. We will now turn to the history of one of the lost diamonds of the Crown, and relate the facts and hypotheses concerning it as fully as we have been able to collect them. They form, indeed, a perplexing theme. The beautiful diamond inventoried as the Sancy, and of the weight of 33¹²⁄₁₆ karats and valued at 1,000,000 francs, was also stolen and never recovered. This gem has been associated with the fortunes of the redoubtable Burgundian warrior, Charles the Bold; and its history has done more to perpetuate his name than the record of all his misdeeds and his desperate battles. To prove, however, that this is the identical gem lost to the Swiss will be a difficult task; for the antiquaries have unearthed more Sancy diamonds than there were “Richmonds in the field.” The name of Sancy has, indeed, become famous by embracing in one story the fortunes of three distinct gems. The erudite King has patiently traced out the traditions connected with the name of Sancy, and appears to prove that three stories instead of one are included in the history of Baron Sancy. But the stone that was stolen from the French casket in 1792 is inventoried at the weight of 33¹²⁄₁₆ karats, while the gem that has lately gone back to India, and is supposed to be the stolen gem, weighs quite 54 karats. Here is a new mystery for the antiquaries to clear away; or did Delattre and his associates, who made out this inventory with exceeding care, write 33 instead of 53? The histories of these diamonds are so interesting that we will attempt to repeat them here, following, in part, the views of Mr. King. Not long after the invention, by Berquen, of diamond-cutting by the process of abrasion, Charles the Bold, then in the full blaze of martial glory, submitted to him three large rough diamonds. The native of Bruges succeeded so well in polishing them, that Charles presented him with the princely sum of 3,000 ducats. One of these gems Charles gave to Pope Sextus IV., and it was mounted in the Tiara, where it is said to remain. The second was presented to Louis XI. of France; while the third was reserved by the Burgundian hero, and set in a grotesque manner to be worn as a personal ornament. This jewel, of true barbaric design, was formed of a triangular shape, with the newly cut diamond in the centre. This diamond was ⁵⁄₈ of an inch in its widest diameter, and was shaped as a pyramid, with the apex cut into a four-rayed star in relief. Around the gem were set three large Balais rubies and four magnificent pearls, each more than half an inch in diameter.