THE species to be considered in this chapter includes the varieties emerald and aquamarine, as well as what jewellers understand by beryl. It has many incontestable claims on the attention of all lovers of the beautiful in precious stones. The peerless emerald (Plate I, Fig. 5), which in its verdant beauty recalls the exquisite lawns that grace the courts and quadrangles of our older seats of learning, ranks to-day as the most costly of jewels. Its sister stone, the lovely aquamarine (Plate I, Fig. 4), which seems to have come direct from some mermaid’s treasure-house in the depths of a summer sea, has charms not to be denied. Pliny, speaking of this species, truly says, “There is not a colour more pleasing to the eye”; yet he knew only the comparatively inferior stones from Egypt, and possibly from the Ural Mountains. Emeralds are favourite ring-stones, and would, no doubt, be equally coveted for larger articles of jewellery did not the excessive cost forbid, and nothing could be more attractive for a central stone than a choice aquamarine of deep blue-green hue. Emeralds are usually step-cut, though Indian lapidaries often Beryl, to use the name by which the species is known to science, is essentially a silicate of aluminium and beryllium corresponding to the formula, Be3Al2(SiO3)6. The beryllia is often partially replaced by small amounts of the alkaline earths, caesia, potash, soda, and lithia, varying from about 1½ per cent. in beryl from Mesa Grande to nearly 5 in that from Pala and Madagascar, and over 6, of which 3·6 is caesia, in beryl from Hebron, Maine; also, as usual, chromic and ferric oxides take the place of a little alumina; from 1 to 2 per cent. of water has been found in emerald. The element beryllium was, as its name suggests, first discovered in a specimen of this species, the discovery being made in 1798 by the chemist Vauquelin; it is also known as glucinum in allusion to the sweet taste of its salts. When pure, beryl is colourless, but it is rarely, if ever, free from a tinge of blue or green. The colour is usually some shade of green—grass-green, of that characteristic tint which is in consequence known as emerald-green, or blue-green, yellowish green (Plate I, Fig. 6), and sometimes yellow, pink, and rose-red. The peculiar colour of emerald is supposed to be caused by chromic oxide, small quantities of which have been detected in it by chemical analysis; moreover, experiment shows that glass containing the same percentage amount of chromic oxide assumes the same splendid hue. Emerald, on being heated, loses water, but retains its colour unimpaired, which cannot therefore be due, as has been suggested, to organic matter. The term aquamarine is applied The name of the species is derived from the Greek ???????, an ancient word, the meaning of which has been lost in the mists of time. The Greek word denoted the same species in part as that now understood by the name. Emerald is derived from a Persian word which appeared in Greek as s??a?d??, and in Latin as smaragdus; it originally denoted chrysocolla, or similar green stone, but was transferred upon the introduction of the deep-green beryl from Upper Egypt. The name aquamarine was suggested by Pliny’s exceedingly happy description of the stones “which imitate the greenness of the clear sea,” although it was not actually used by him. That emerald and beryl were one species was suspected by Pliny, but the identity was not definitely established till about a century ago. Morganite is named after John Pierpont Morgan. The natural crystals have the form of a six-sided prism, and in the case of emerald (Fig. 70, and Plate I, Fig. 8) invariably, if whole, end in a single face at right angles to the length of the prism; aquamarines have in addition a number of In all probability the whole of the emeralds known in ancient times came from the so-called Cleopatra emerald mines in Upper Egypt. For some reason they were abandoned, and their position was so completely lost that in the Middle Ages it was maintained that emeralds had never been found in Egypt at all, but had come from America by way The products of none of the mines that have just been mentioned can on the whole compare with the beautiful stones which have come from South America. At the time when the Spaniards grimly conquered Peru and ruthlessly despoiled the country of the treasures which could be carried away, immense numbers of emeralds—some of almost incredible size—were literally poured into Spain, and eventually found their way to other parts of Europe. These stones were known as Spanish or Peruvian emeralds, but in all probability none of them were actually mined in Peru. Perhaps the most extraordinary were the five choice stones which Cortez presented to his bride, the niece of the Duke de Bejar, thereby mortally offending the Queen, who had desired them for herself, and which were lost in 1529 when Cortez was shipwrecked on his disastrous voyage to assist Charles V at the siege of Algiers. All five stones had been worked to divers fantastic shapes. One was cut like a bell with a fine pearl for a tongue, and bore on the rim, in Spanish, “Blessed is he who created thee.” A second was shaped like a rose, and a third like a horn. A fourth was fashioned like a fish, with eyes of gold. The fifth, which was the most valuable and the most Emerald, unlike some green stones, retains its purity of colour in artificial light; in fact, to quote the words of Pliny, “For neither sun nor shade, nor yet the light of candle, causeth to change and lose their lustre.” Many are the superstitions that have been attached to it. Thus it was supposed to be good for the eyes, and as Pliny says, “Besides, there is not a gem or precious stone that so fully possesseth the eye, and yet never contenteth it with satiety. Nay, if the sight hath been wearied and dimmed by intentive poring upon anything else, the beholding of this stone doth refresh and restore it again.” The idea that it was fatal to the eyesight of serpents appears in Moore’s lines— “Blinded like serpents when they gaze Upon the emerald’s virgin blaze.” The crystals occur attached to the limestone, and are therefore never found doubly terminated. The crystal form is very simple, merely a hexagonal prism with a flat face at the one end at right angles to it. They are invariably flawed, so much so that a flawless emerald has passed into proverb as unattainable perfection. The largest single crystal which is known to exist at the present day is in the possession of the Duke of Devonshire (Fig. 71). In section it is nearly a regular hexagon, about 2 inches (51 mm.) in diameter from side to side, and the length is about the same; its weight is 276·79 grams (9¾ oz. Av., or 1347 carats). It is of good colour, but badly flawed. It was given to the Duke of Devonshire by Dom Pedro of Brazil, and was exhibited at the Great Exhibition of 1851. A fine, though much smaller crystal, but of even better The ever great demand and the essentially restricted supply have forced the cost of emeralds of good quality to a height that puts large stones beyond the reach of all but a privileged few who have purses deep enough. The rate per carat may be anything from £15 upwards, depending upon the purity of the colour and the freedom from flaws, but it increases very rapidly with the size, since flawless stones of more than 4 carats or so in weight are among the rarest of jewels; a perfect emerald of 4 carats may easily fetch £1600 to £2000. It seems anomalous to say that it has never been easier to procure fine stones than during recent years, but the reason is that the high prices prevailing have tempted owners of old jewellery to realize their emeralds. On the other hand, pale emeralds are worth only a nominal sum. The other varieties of beryl are much less rare, and, since they usually attain to more considerable, and sometimes even colossal, size, far larger stones are obtainable. An aquamarine, particularly of good deep blue-green colour, is a stone of great beauty, and it possesses the merit of preserving its purity of tint in artificial light. It is a favourite stone for pendants, brooches, and bracelets, and all purposes for which a large blue or green stone is desired. The varying tints are said to be due to the presence of iron in different percentages, and possibly in different states of oxidation. Unlike emerald, the other varieties are by no means so easily recognized by their colour. Blue aquamarines may easily be mistaken for topaz, or vice versa, and the yellow beryl closely resembles other yellow stones, such as quartz, topaz, or tourmaline. Stones which are The splendid six-sided columns which have been discovered in various parts of Siberia are among the most striking specimens in any large mineral collection. The neighbourhood of Ekaterinburg in the Urals is prolific in varieties of aquamarine; especially at Mursinka have fine stones been found, in association with topaz, amethyst, and schorl, the black tourmaline. Good stones also occur in conjunction with topaz at Miask in the Government of Orenburg. It is found in the gold-washings of the Sanarka River, in the Southern Urals, but the stones are not fitted for service as gems. Magnificent blue-green and yellow aquamarines are associated with topaz and smoky quartz in the granite of the Adun-Tschilon Mountains, near Nertschinsk, Transbaikal. Stones have also been found at the Urulga River in Siberia. Most of the bluish-green aquamarines which come into the market at the present time have originated in Brazil, particularly in Minas Novas, Minas Geraes, where clear, transparent stones, of pleasing colour, in various shades, are found in the utmost profusion; beautiful yellow stones also occur at the Bahia mines. Aquamarine was obtained in very early times in Coimbatore District, Probably the largest and finest aquamarine crystal ever seen was one found by a miner on March 28, 1910, at a depth of 15 ft. (5 m.) in a pegmatite vein |