The famous opal of history was that which was worn in a ring by the Roman Senator Nonius in the days of the Triumvirate. Its size scarcely exceeded that of a hazel-nut, yet its beauty and perfection were such that it was considered a marvel among the _dilettanti_ of Rome, and valued at the enormous sum of nearly a million dollars. Marc Antony, remembering the sacrifice of the matchless pearl by Cleopatra, and still enslaved by her irresistible charms, sought to obtain the opal, intending it as a present to the siren queen of Egypt. But Nonius refused to part with the treasure which was the idol of his heart, and sought safety in flight. The beauty and charm of the gem may be estimated by the fact that banishment then to a Roman was worse than death. History makes no further mention of this wonderful opal, and even if preserved among the spoils of ancient Byzantium its glories have probably vanished ere this, yielding to the destructive effects of time. The finest opal of modern times was that which was worn by the Empress Josephine in the days of Imperial splendor. It was indeed a magnificent gem. Its flashing beams of light were so strong and vivid as to give the appearance of living flames of fire, and hence the name of _l’incendie de Troie_,--“the burning of Troy,”--was bestowed upon it. The base of this opal was completely opaque, but the superior portion was perfectly transparent, and through it were reflected a multitude of fiery gleams of red light. The fate of this beautiful gem is unknown. There are two splendid opals still to be seen among the Crown jewels of France, notwithstanding the frequent change of dynasties. One is placed in the centre of the Order of the Toison d’Or, and the other forms the clasp of the royal mantle. In the imperial cabinet at Vienna is exhibited the grandest specimen of this gem yet discovered. It was found in the mines of Hungary in 1770, and purchased by the Austrian Government. It measures 3³⁄₄ inches in length, and is 2¹⁄₂ inches in thickness. Its weight is about seventeen ounces, and its value is estimated at about $300,000. Although it is injured by several cracks and fissures, it possesses a brilliant play of color, and is justly regarded as the finest specimen known, even surpassing the beautiful fire opal brought home from Mexico by Humboldt, and which is still preserved in the museum at Berlin. At the close of the last century, but before the Revolution broke out in France, Mons. D’Auguy, a financier of Paris, came in possession of a most remarkable opal of the harlequin variety. It was of oval form, ⁷⁄₈ of an inch in length by ⁵⁄₈ in breadth. This gem was of wondrous beauty, and was pronounced perfect by the connoisseurs. It is now in the hands of the family of Count Waliski. At the same time the well-known amateur Fleury owned a rival to Auguy’s opal, which it exceeded slightly in size.