This custom of using the rough gems prevailed to some extent in recent times; and De Laet states that as late as the middle of the seventeenth century rough spinels were preferred to the cut for ornamentation. However, we will briefly allude to one or two instances in history, which lead the reader to infer that the diamond received a definite polish at an early day. Chrysostom, an authentic writer of the fourth century, in describing the magnificence of the Greek emperors at Byzantium, mentions the dazzling splendor of the diamonds scintillating by agitation. If the historian does not use this description for the gems in general, we may infer that the diamonds had been polished; since the unpolished stones do not exhibit much, if any, play of the prismatic hues. The maxim, “diamond cut diamond,” is of ancient origin, and may perhaps be referred to the saying in vogue among the Greeks as early as the seventh century, “that for the purpose of cutting diamonds, a diamond was most effectual.” The accounts of the Oriental historians concerning the fêtes of Timour in the fourteenth century, where diamonds were showered in profusion upon the guests, leave no doubts as to the art of polishing the gem as early as that period. The inventory of the _joyaux_ belonging to the Duc d’Anjou, in 1360, shows that diamonds were then cut, although rudely. It makes special mention of several diamonds, and one in particular set in a reliquary, and cut in escutcheon. Other polished diamonds are described in the account given of the splendid entertainment given at the Louvre, by the Duke of Burgundy, to the King and Court of France. There is also evidence to prove that diamond lapidaries were at work in Paris, when Berquen came to reside there. However, it was not until 1475, after Berquen returned to his native city, Bruges, that the mode of polishing diamonds by direct abrasion became known in Europe. And when Charles the Bold intrusted the three famous gems to his skill, and rewarded him with 3,000 ducats for his labor, the name of Berquen became famous and widespread throughout Europe. Nearly two centuries after this success, Cardinal Mazarin attempted to establish the business of diamond-cutting in Paris, and confided to the lapidaries he had invited to reside there, twelve of the finest diamonds belonging to the Crown to be recut. These gems, from their beauty, and the circumstance of cutting, were called the twelve Mazarins. History has neglected to record the fate of these magnificent gems save one. In the inventory of the French jewels in 1791, there is the solitary description, “the tenth Mazarin.” The others have disappeared.