The famous mirror or lens, in or through which the cruel and near-sighted Nero was wont to view the bloody combats in the arena at Rome, is supposed to have been cut from an emerald; but it was probably a lens cut from green glass.

It appears, however, from the researches of the antiquaries, that the gem was very rare until the Imperial epoch, when they were introduced from Asia and other countries in accordance with the luxury and extravagance of the age. Castellani’s collection displays some fine examples of the jewelry of this period set with emeralds. Among them there is a beautiful necklace formed of sixteen natural crystals of emerald fastened in gold; and also another composed of ten natural crystals of emerald set in double chains of gold. Among the engraved gems may be seen an emerald intaglio, representing a Nereid on a sea bull, and two other intaglios of beryl, with pictures of Mars, and a portrait of Julia Paula.

From the earliest times of history monarchs and potentates of all ranks and races, from Solomon to Montezuma, were wont to wear signet rings, which were sometimes engraved, and were then often used to impart authority either by the exhibition of the ring itself, or its impression upon papyrus, parchment, or wax. The most celebrated ring of this description we have any authentic knowledge of, was that formed of a large emerald set in gold and worn by Alexander the Great, whose portrait was engraved upon the stone. The hero, when dying, bestowed it upon his favorite general, Perdiccas, and thereby invested him with the authority of succession. History refuses to make known the fate of this splendid gem. It is probable that Ptolemy Soter obtained possession of it when Perdiccas was slain in Egypt, and that eventually Augustus Cæsar may have worn it for his first imperial seal, which was an emerald engraved with the head of Alexander.

After the death of Pompey in Egypt, his seal ring, which represented a lion holding a sword in his paw, was taken to Rome and presented to Cæsar, who burst into tears on receiving the signet of his former associate and unfortunate rival.

The practice of interring with the dead some of the jewels worn in life, has been practised in recent times. When Cardinal Borromeo was buried at Milan two hundred years ago or more, a large gold cross, containing seven large and fine emeralds surrounded with diamonds, was placed in his tomb. When Lord Palmerston was buried at Westminster Abbey, the officiating clergyman threw into the grave several diamond and gold rings as a peace offering. In ancient times the custom was of frequent occurrence, and to this habit we owe the preservation of many beautiful gems and jewels, which have in this manner escaped the pillage and fury of thieves and iconoclasts.

The mineral has borne the name of emerald since the middle of the seventeenth century, at which time it was adopted by the mineralogist, Wallerius. But whence it is derived, and on what particular grounds, we are not informed. In Asia, in ancient times, it was described under the Sanskrit name, “marakat,” which is connected with “esmark,” signifying a sea monster, or “makara,” meaning the sea. As it passed westward, among the Persians it became “zabargat,” and still farther on its journey it was changed by the Greeks and Latins into “smaragdus.” The derivation of its ancient terms is also exemplified by the use or purposes in which the gem and its varieties were used. It was therefore frequently chosen by the antique gem cutters and engravers, as the proper material for the representation of all maritime subjects or any allusions to the sea gods.

The emerald is now one of the rarest of gems; and its scarcity gives rise to the inquiry as to what has become of the abundant shower of emeralds which fairly rained upon Spain during the early days of the conquest of Mexico and Peru, bringing down the value of fine stones to a trifling price. As with all commercial articles, there is a waste and loss to be accounted for during the wear of three centuries; but this alone will not explain their present rarity in civilized countries. Even in the times of Charles II., when the destitution of the country was extreme, the Dukes of Infantado and Albuquerque had millions in diamonds, rubies, and precious stones, yet hardly possessed a single sou. So impoverished was the land, and so slender were the purses of all, that the Duke of Albuquerque dined on an egg and a pigeon, yet it required six weeks to make an inventory of his plate. At this period, when the nobles gave fêtes the lamps were often decorated with emeralds and the ceilings garlanded with precious stones. The women fairly blazed with sparkling gems of fabulous value, while the country was starving. Most, if not all, of this missing treasure was transferred to Asia, and with the silver current which flowed steadily from the Spanish coffers into India went many of the emeralds also; for in those regions this gem is regarded as a foreign stone, and the natives, investing it with the possession of certain talismanic properties, prize it above all earthly treasures.

When the Spaniards commenced their march toward the capital of Mexico, they were astonished at the magnificence of the costumes of the chiefs who came to meet them as envoys or join them as allies; and among the splendid gems which adorned their persons they recognized emeralds and turquoises of such rare perfection and beauty that their cupidity was excited to the highest degree. During the after years of conquest and occupation the avaricious spoilers sought in vain for the parent ledge where these precious stones were found. Recent times have, however, revealed the home of the Mexican turquoise, which has proved to be in the northern part of Mexico, as the Totonacs informed the inquiring Spaniards. The first of these mines, which is of great antiquity, is situated in the Cerrillos Mountains, eighteen miles from Santa Fé. The deposit occurs in soft trachyte, and an immense cavity of several hundred feet in extent has been excavated by the Indians while searching for this gem in past times. Probably some of the fine turquoises worn by the Aztec nobles at the time of the Spanish Conquest came from this mine. Another mine is located in the Sierra Blanca Mountains in New Mexico, but the Navajos will not allow strangers to visit it. Stones of transcendent beauty have been taken from it, and handed down in the tribe from generation to generation as heirlooms. Nothing tempts the cupidity of the Indians to dispose of these gems, and gratitude alone causes them to part with any of these treasures, which, like the mountaineers of Thibet, they regard with mystical reverence. The Navajos wear them as ear-drops, by boring them and attaching them to the ear by means of a deer sinew. Lesser stones are pierced, then strung on sinews, and worn as necklaces. Even the nobler Ute Indians, when stripping the ornaments of turquoise from the ears of the conquered Navajos, value them as sacred treasures, and refuse to part with them even for gold or silver.

All the Spanish accounts of the invasion of Mexico agree in the great abundance of emeralds, both in the adornment of the chiefs and nobles and also in the decoration of the gods, the thrones, and the paraphernalia. The Mexican historian Ixtlilxochitl says the throne of gold in the palace of Tezcuco was inlaid with turquoises and other precious stones; that a human skull in front of it was crowned with an immense emerald of a pyramidal form.

The great standard of the republic of Tlascala was richly ornamented with emeralds and silver-work. The fantastic helmets of the chiefs glittered with gold and precious stones, and their plumes were set with emeralds. The mantle of Montezuma was held together by a clasp of the green chalchivitl (jade), and the same precious gem, with emeralds of uncommon size, ornamented other parts of his dress.