Gemma (λίθος). A precious stone. The art of cutting gems was learned by the Greeks, at an early period, from the Egyptians, who had practised it from remote antiquity. The Aethiopians used engraved stones as coins (λίθοι ἐγγεγλυμένοι), and engraved seals may have been used for money in Greece prior to the invention of coinage. At first the cutting was only concave, the gems being set in rings and used as seals. The subjects are usually human or animal forms, especially lions, bulls, and horses. The oldest Greek gems, numbers of which have been found at Mycenae and Ialysus, are bean-shaped (“lenticular”) or pebble-shaped (“glandular”), differing thus from the cylinders and scarabs of Assyria and Egypt. Cameos or stones carved in relief first came into use, it would seem, in the time of Alexander the Great, and were used as ornaments. For cameos precious stones of various colours were used, especially the onyx. The layers of the stone were so treated that the figures stood out vividly on a dark ground. Mnesarchus of Samos, the father of the philosopher Pythagoras (about 600 BC) is the oldest Greek jeweller whose name has come down to us. In the fourth century B.C.

the most celebrated master was Pyrgoteles, the only artist whom Alexander the Great would allow to cut his likeness. In the age of Augustus we hear of Dioscorides, who cut the emperor's likeness on a stone which was used as a seal by the succeeding Caesars. The Etruscans and Romans took up the art very early, but never attained the same perfection as the Greeks, importing gems largely from both Greece and Egypt. The scarab or beetle-shaped gems, so little valued by the Greeks, were intensely admired by the Etruscans, whose art in so many respects exhibits Egyptian characteristics

The fashion of making collections of beautiful gems arose as early as the first century B.C. The intaglios, or cut stones, have come down to us in greater numbers than any of the monuments of ancient art. Those which belonged to the advanced periods of style present examples of the most beautiful workmanship, the most original composition, and the most interesting subjects, the latter being mainly taken from mythology. Among the remaining Greek cameos an important place, both for size and beauty, must be given to the Gonzaga Cameo in St. Petersburg. This, it has been conjectured, represents the bust of Ptolemy Philadelphus and Arsinoé, his sister and wife; though it more probably commemorates Nero and Agrippina. The largest and most splendid of the cameos which have come down from the Roman period are those at Vienna and Paris, representing, in groups and figures, the family of Augustus. Gems engraved with humorous designs were called grylli. (See Antiphilus.) These usually combined half a dozen incongruous forms arranged into the semblance of some well-known object, and occasionally with a hidden meaning. Thus, the accompanying example from a gem in the King Collection is made up of a wolf, a boar, and a lizard so blended as to form a helmet, the emblems respectively of Mars, Minerva, and Mercury.

Whole vessels were sometimes made of single stones, and adorned with reliefs. An instance is the Mantuan Vase now at Brunswick, 6 1/3 inches high, 2 1/3 inches thick, consisting of a single onyx. The lid, handle, and base are of gold. Two parallel lines of gold divide the surface into three parts, the middle one of which has twelve figures, representing the festival of the Thesmophoria, in three groups; while the highest and lowest are adorned with leaves, flowers, ears of corn, fruits, bulls' heads, and other objects connected with the worship of Demeter. Works of this kind were sometimes made of coloured glass. The most celebrated instance of this sort is the Portland Vase, found filled with ashes in the tomb of Alexander Severus, and now in the British Museum. Its height is about 10 inches. The material is a dark blue transparent glass, with beautiful reliefs in white opaque enamel.

Herodotus (vii. 69) speaks of a sharp stone as being used in engraving gems. Many of the ancient gems, especially those used as coins, were engraved with obsidian, of which knives were made. A minute metal disk with a sharp edge and worked by a drill was used in cutting the deeper parts of the pattern. (Cf. Pliny, H. N.xxvii. 76; and Murray, Handbook of Greek Archaeology, pp. 147-148). A sort of emery-powder (smyris) was employed to charge the tools. The crustae of diamonds and fragments of ostracitis were used as diamond-points.

For some account of the extraordinary profusion of precious stones in the East and among the successors of Alexander, see Diod. Sic.xviii. 26; Athen. xi. p. 781; Strab.xv. p. 718, and other passages quoted by Krause, Pyrgoteles, p. 113. The extravagant luxury of the Romans of the Empire rivalled that of the Diadochi.

Pearls and emeralds were the favourite stones of the Romans. Iulius Caesar gave Servilia, the mother of Brutus, a pearl worth 6,000,000 sesterces . The famous pearl which Cleopatra dissolved and drank was one of a pair set in ear-rings, and worth 10,000,000 sesterces . Claudius Aesopus, son of the great actor, in imitation of this feat, did the same thing, snatching, however, the gem from the ear of Caecilia Metella, a beauty of the day. Caligula wore pearls on his shoes; Nero had them sprinkled over his bed-coverings. Pliny tells how, at a wedding party—a rather quiet affair—Lollia Paulina, the wife of Caligula, was covered with pearls and emeralds which shone in alternate rows on her head, neck, and fingers, and of which the cost was 40,000,000 sesterces , as she proved by showing to him the receipted bills for them. “Pearls,” he says in another place, “are the quintessence of extravagance.” Claudius used an emerald as an eye-glass with which to watch the circus games. The opal was also much admired, and Pliny tells how one Nonius was proscribed by Antony the triumvir so that he might be robbed of a magnificent opal in his possession. Pliny also speaks of the ruby (carbunculus) and the amethyst as much esteemed. (See Amethystus.) The ancients perhaps knew of the diamond, but could not have properly valued it, since the art of polishing and cutting it was not learned until it was discovered in modern times by Berquier of Bruges in the fifteenth century. (See Adamas.) Besides being worn in rings, gems were set in armillae or bracelets in many forms, including spirals and bangles; in monilia or necklaces of consecutive rows, one found at Pompeii having seventy-one pendants; and in ear-rings. (See Inauris.) Jewels also profusely adorned the drinking-cups used at banquets, and the dainty little boxes of gold and silver used by the ladies in the mysteries of their toilets.

As might be expected, there was a large traffic in imitations of the precious stones, executed in both paste and glass, and with much fidelity. Pliny ( Pliny H. N.xxxvii. 197) speaks of “glass jewels in cheap rings” for the lower classes; and there exist

to-day at Rome collections of these imitations which cannot be distinguished from the genuine stones by the eye. (See Vitrum.) The stone most successfully copied was the emerald, but we hear of counterfeits of the amethyst, ruby, and sapphire.

This passion on the part of the wealthy for precious stones was naturally favourable to the growth of mineralogical knowledge. Pliny quotes a large number of writers who had treated of gems between Theophrastus and himself. Some of these writers seem to have had a personal knowledge of India. Pliny devotes the final book of his Historia Naturalis to gems, regarding them as the most perfect works of nature. The book consists of an historical introduction ( 1-5); of an account of the most important gems, arranged by colours ( 6-54); and an account of minor gems in alphabetical order. The book concludes with a few general instructions for detecting fraud. This book, which is the best representative of ancient science in this branch of mineralogy, shows us that the ancients were remarkably close observers of gems, availing themselves of all methods, short of chemical analysis and other instruments of modern physical research. Moreover, in the case of precious stones, minuteness of observation was stimulated by the desire of guarding against or of committing a fraud ( H. N.xxxvii. 197 foll.). Besides a minute study of colours of gems, frequently illustrated by Pliny 's felicitous comparisons, the tests enumerated involve a study of weight, consistency (corpus), hardness, conductivity, transparency, diffractive power, friction, taste, and smell.

There are no traces in Theophrastus of magical properties attributed to gems. In Pliny, the doctrines of the Magi are frequently quoted, but usually with ridicule. Some of the medicinal virtues of gems apparently accepted by Pliny may appear little better than the doctrines of the Magi. But while Pliny is not in a position to criticise the alleged virtues of gems applied as medicine, he consistently rejects their supernatural powers under other conditions. The magical system is seen fully developed in the Lithica of Orpheus. (See Amuletum.) This poem claims to be a statement of the magic properties of gems made by the seer Theodamas to the poet Orpheus. The work is generally assigned to a time subsequent to the edict of Constantius against magic, in A.D. 357, and not long after Valens, although Krause (Pyrgoteles, p. 6) ascribes it to the fifth century b.c.; and King dates it “at least as early as the second century B.C.” The latter scholar gives an English verse translation (Precious Stones, p. 375).

Much confusion and uncertainty exist as to the true nomenclature of gems. Both in ancient and modern times there has been considerable looseness of usage as to the meaning of names. In many instances where the ancient word exists in modern language, it denotes a stone entirely different from that originally signified. For example, σάπφειρος is certainly the lapis lazuli, and has no connection with the sapphire, which was called hyacinthus.