The museums of Europe contain many examples of mediæval and modern engraved sapphires, one of the finest of which is the famous portrait of Pope Paul III. among the Pulsky gems, and attributed to Il Greco. It is a very beautiful stone, and three quarters of an inch square. In the Marlborough cabinet there is an extraordinary specimen of a thumb ring of high antiquity, cut from a single stone, but of rather a pale tint. Rings containing both plain and engraved sapphires have been the appointed symbol of church authority from a very early day. They have often been bestowed as the badge of pontifical rank, and the custom has descended to the present day. King devotes an interesting chapter to the history and description of this class of ornaments and symbols; and to his pages we must refer the interested reader. Engraved red sapphires of ancient date are extremely rare, so rare that the experienced antiquaries, Lessing and Clarac, deny the existence of any antique intaglios of this variety. Investigation has proved that many of the supposed engraved rubies are really red spinel, garnet, or zircon. Nevertheless, there are a few examples to prove that the ancients did make use of the gem in the glyptic art, although the act was regarded as one of extreme extravagance, from the rarity, costliness, and beauty of the material. The Devonshire parure exhibits a convex red sapphire of about three karats weight, of pure pigeons’-blood tint, and engraved with a Venus Victrix in the latest Roman manner. Another shows a full-length figure of Osiris, in half-relief, of the time of Hadrian. In the museum of the Jardin des Plantes there are said to be two engraved red sapphires. There are but few gems with which the blue sapphire can be confounded. The blue diamond can be easily detected by its superior brilliancy and hardness. It is very rare that the tourmaline appears of a deep blue, and still more rare for the topaz to assume the appearance except of the very light varieties, and the same may be said of the beryl. The iolite, which, however, is a very rare mineral, may resemble the blue sapphire, but its inevitable dichroism betrays its character. Turn the gem before the eye, and the deception vanishes; the blue disappears as if by magic, and the stone is gray. Kyanite sometimes appears of the most beautiful blue tints, but its softness indicates its nature, and prevents its use as a gem. The glass-workers, however, produce the most beautiful and attractive imitations of sapphire, and of all colors, lacking but one desideratum, and that is the thus far unattainable degree of hardness. The red, green, yellow, and white varieties may all of them be closely approached in color by other gems, and the best methods of detection are the tests of specific gravity, degree of hardness, and the optical phenomena.