Rings entirely of precious-stone material, or “hololith” rings, have been found at Mycenæ, one of jasper and another of rock-crystal, and a carnelian ring was discovered in a tomb in southern Russia. Each of these bears an engraved design. Two carnelian rings are in the British Museum. Chalcedony rings, that is, rings entirely formed of this stone, while quite rare, are represented by a few specimens. We describe elsewhere the so-called betrothal ring of the Virgin at Perugia,[164] and the British Museum has a large example of a chalcedony ring, with the hoop rounded on the outer side, and a raised bezel that has been roughly cut so as to indicate a human head, some scratches marking the hair. The work is late Roman and the inscription shows that it was made for some adherent of the Gnostic sect.[165] A large ring, entirely of rock crystal, shows on the oval flattened surface of the upper part a curious combination of the “Tau Cross,” with superposed “chrisma,” and with a serpent twined about it, recalling the brazen serpent of Moses, the view of which restored health to the diseased; the Greek letters, _alpha_ and _omega_, “the beginning and the end,” complete this interlacing of Old and New Testament emblems; the doves facing the cross are the faithful to whom the Cross of Christ brings salvation.[166] Another entire crystal ring bears on its flat face a design of somewhat similar import, with, however, the curious difference that the lower end of the cross is supported on a little Cupid, on either side of which figure is a dove.[167]