THE EMERALD

Of all green things which bounteous earth supplies, Nothing in greenness with the emerald vies. Thus wrote, in Latin, a certain Abbot Morbodeus in the Eleventh Century. But long before, Pliny had written that "After the diamond and the pearl, the third place is given to the emerald for many reasons. No other color is so pleasing to the sight, nothing equals them in the intensity of its green. Besides, they are the only gems that fill the eye with their view but yet do not fatigue it; nay, more, when the sight is wearied by any over-exertion, it is relieved by looking at an emerald." We can see, therefore, that this gem stone was regarded with the greatest esteem even in the earliest days of civilization. In the East, it was a favorite stone, not only on account of its fascinating color, but also because it could be engraved with ease. For although its actual rarity and its beautiful color have always placed it in the front rank of precious stones, its hardness is be­low that of ruby and sapphire.

The treasuries of India, Persia, the U.S.S.R., and Turkey con­tain priceless emeralds, many of which are of great antiquity. Some of the finest specimens are engraved as seal stones, and many such examples have been found in the ruins of Thebes and elsewhere. We are told that the ring of Polycrates, engraved by Theodore of Samos, was an emerald, and Pliny mentions that, when Lucullus landed at Alexandria,

Ptolemy, King of Egypt, presented to him an emerald set in gold and engraved with his portrait. Such specimen stones would be handed down through die centuries and only occasionally would they find their way to public museums. As comparatively late as the year 1804, the Pope was presented with an antique emerald which bore the name of Jules II. Emerald is only one of the larger group of stones which falls under the general name of beryl. Other stones of the same composition are aquamarine, morganite, and the various brown, yellow, and pale green beryls, only their color distinguishing them from the precious emerald. We will describe these other varieties of beryl in a later chapter. It is the beautiful velvety, deep trans­parent green which makes the emerald so esteemed, and its beauty, coupled with its actual rarity of occurrence in unflawed specimens, makes it one of the most costly of the precious stones. Beryl is a silicate of aluminum and beryllium, and the varia­tion in color which it displays is probably due to very small in­cluded quantities of different metallic oxides. The green color of emerald is no doubt due to a minute percentage of chromic oxide being present, although the darker stones are thought to contain some organic matter. The application of heat, however, does not seem to affect the color.

Emeralds are generally found in the parent rock, which is often a mica schist, and crystals in the form of hexagonal prisms (hex agonal system) are common. These crystals are nearly always flawed; some even flaw on being mined and exposed to the air, and clear, fine stones are very rare. On the other hand, aqua marine and other forms of beryl are quite often found in comparatively large and flawless crystals. Cracks and inclusions, of course, lessen the value of stones; the pale shades are not so valuable, and it is the deep, velvety green, enhanced by a vitreous luster which makes the fine emerald so attractive. Among the physical properties of emerald are its comparatively low degree of hardness and its low specific gravity. Hardness is only 7 1/2 to 7 3/4, and specific gravity only 2.74 (but some stones may fall between the limits of 2.67 and 2.75); moreover, the stone is very brittle, which necessitates careful handling when being cut and set in jewelry. Stones will scratch after some wear, and careful repolishing will be required.

The brilliant form of cutting is very rarely used; step cut is the most usual. Other properties are its refractive indices, 1.57-1.58, its almost total lack of cleavage, and its weak dichroism except in well col­ored specimens. Acids have no effect on this stone, but it may befused by means of a blowpipe. Its color, also, is not largely affected by artificial light. Other green stones are visibly affected, and this had been noticed in very early days. Pliny wrote of emeralds that "Neither dim nor shade, nor yet the light of a candle, causes them to lose their lustre." The principal localities where emeralds are found are Colombia (South America), Egypt, the Urals, South Africa, Brazil, and New South Wales. The finest stones have come from the South Ameri­can mines for many centuries, although the earliest stones men­tioned in history no doubt came from the mines in Upper Egypt. At present, the only important producing areas are Colombia, South Africa, and Siberia. The Egyptian mines were situated in a range of mountains running parallel to the western side of the Red Sea. They were worked in Biblical days, and here was the source of the emeralds mentioned in the Bible. Many of the ancient scarabs came from these mines, as did also the famous engraved stone which was presented to Cleopatra. The ruins of these mines were rediscovered by the French explorer Caillaud about a century ago. He found them in almost the same state as they had been left by the Ptolemies. Extensive causeways, ropes, baskets, levers, lamps, and other tools were found in a good state of preservation. Some of the excavations had been carried out to a depth of 800 feet, and others were so large that 400 workmen could be accommodated. Facilities for conveying provisions by camels had evidently been provided, and a village of some 500 houses in good condition was unearthed a short distance from the quarries. But there was also evidence to prove that the mines had been worked about a century before the arrival of Caillaud. However, he found some 10 lbs. in weight of emeralds, which were of a pale green color, cloudy and flawed, and these were handed to the Pasha of Egypt.

The Russian emerald mines in the Urals were accidentally dis­covered by a peasant in the year 1830. Since then, many stones have been found, a number being of large size, but they are often pale in color and very flawed. For many years, mining has been controlled by the Government and the nature of the output is difficult to assess, but many of the stones are also cut locally. The emerald market is very little affected by fresh material coming from this area; indeed, very few new stones of good quality appear from any part of the world, and the finest emeralds in jewelry today are old stones, or stones that have been re-cut and re-polished. At present, the Colombian mines are also being operated on a very small scale, and gem material from other districts is almost negligible. Stones from Brazil, chiefly from the state of Bahia, are pale and flawed, although several districts here are capable of further development should the demand for pale emeralds in-(lease. Between the years 1927 and 1929, a few emeralds were found in the Poona district of West Australia. Previously, in 1920, some 600 carats valued at $778 (£278) were found on the Murchison gold field.

Beryl ore of non gem quality, but used in special alloys, is also found in West Australia. A few stones found in Burma, near Mogok and in the sands of the river Irrawaddy, were also of little commercial value. A fairly recent discovery was located at Mewar in Rajputana (India), but again no stones of importance have come from here as yet. Chiefly of historical interest is an emerald mine near Salzburg (Austria), which dates back to Roman times. It is situated in the mountains near Habachthal, and some good stones were pro­duced here many years ago. In 1896, it was acquired by a British company, who later sold it, after having very little success, to a group of local workers in 1913. In 1928, the mine was advertised for sale, and ten years later it was reopened, but subsequent work ing produced very few stones. Two large mines have been worked in South Africa, but for some years now, very little material has been produced. Under ground mining followed the open cast method, and stones have been found in many districts, particularly around Letaba in N.E. Transvaal. Since their discovery in 1927, about 846,000 carats realizing $269,982 (£96,422) have been produced, but the main mines were closed down in 1939. South African emeralds are, however, invariably of poor quality, and their origin can be recognized without much difficulty.

Mostly flawed, and badly flawed at that, their color is usually a dark bluish-green, in contrast to the Russian and Brazilian stones now being mined, which are nearly always a pale green. In December 1929, a company was formed to exploit mines dis­covered in the Leysdorp district, also in South Africa. Here, the stones, with other varieties of beryl, occur in the usual mica schist, and they are frequently accompanied by tourmaline, quartz, apatite, feldspar, and molybdenite. But few good stones have been found; they are usually cracked and of a cloudy, dark color, being similar in quality to other emeralds found in South Africa. A few stones have been imported in recent years from India (Ajmer), and these are of good color, although small. They show rather strong dichroism.

Their number, however, is so small that they have not affected the market in any way. It will be seen, therefore, that all recent discoveries of emeralds have yielded comparatively few stones, and none of these has been of fine color and quality. The finest emeralds one sees are most probably old stones from South America, and no other known area has yet rivalled this source for beautiful deep green stones. Emeralds were mined and treasured in South America long before the white man spread his benign influence over that vast and rich continent. The fact that this precious mineral was well known to the natives was conveyed to Europeans through the Spaniards, who visited Colombia in the Sixteenth Century. Some of these adventurers worked the mines with the help of the na­tives, and some fine stones found their way to Spain. The situation of the mines was near the Garagon river, about 27 miles from Guateque, east of Bogota. According to Fray Simone, the historian who described the Spanish conquest of South America, the emerald mines of Chivor are situated on the point of a ridge "from which the llanos of the Orinoco can be seen." After about the year 1600, these mines seem to have been abandoned, perhaps because of the more productive Muzo mines which were discovered in 1558. These were found by accident, although no doubt the natives were well aware of this source long before the Spaniards tried to discover it. Emeralds, and other precious stones, were regarded by the native Aztecs of Mexico with great esteem. Cortes sent priceless treasures to the Emperor of Spain in the year 1525, among which was an emerald as broad as the palm of the hand. This stone came from the halls of justice at Tezenco, where a cere­monial throne of gold, inlaid with turquoises and precious stones, stood. In front of this throne was a stool, on which was placed a human skull, crowned with this enormous emerald.When Cortes returned to Spain, he brought five emeralds of wonderful size and brilliancy with him. These gems had been cut by the Aztecs into the shape of flowers, fishes, and into other fanciful forms with a fine degree of workmanship. One stone was in the form of a rose, the second in that of a horn, a third like a fish with eyes of gold.

The fourth was fashioned like a little bell, with a fine pearl for the striker, and the fifth was a small cup with a foot of gold. Merchants of Seville offered Cortes 40,000 ducats for one of these gems, but he rejected this offer. He presented them to his wife, a niece of the Duke of Bejar, on their marriage, but this incurred the displeasure of the queen, and Cortes thereafter lost favor with the king. Within a few years, he returned to Mexico again, out of favor with the court, and a disappointed man. No doubt these emeralds were a part of the treasure of the unfortunate Montezuma. The first landing by the Spaniards under Pizarro on the coast of Peru in 1531 resulted in the capture of an enormous quantity of precious stones, as well as a large number of valuable gold and silver ornaments. Of the stones, emeralds were the most abun­dant, and one, which fell into the hands of Pizarro, was as large as a pigeon's egg. Unfortunately, his followers did not understand the value of such gems, and they broke many into fragments by pounding them with hammers. It is recorded that they were en couraged in this destruction by one of the accompanying mission­aries, Fray Reginaldo de Pedraza, who assured them that this was the'right method of testing a real emerald. He asserted that true stones would not be affected by such treatment. But it was ob served that the good father did not subject his own jewels to this test. As a result, however, these green stones were disdained by the Spaniards for a while, and they began to regard them as merely colored glass.

But when this Dominican missionary returned to Panama, he carried back with him a considerable number of valuable emeralds, which he sold at huge prices. In 1896, the old mines were rediscovered by a Colombian en gineer, Pacho Restrepo, quite by chance, and he founded the Chivor Emerald Mine Company to exploit the ground. Chivor had been abandoned after the discovery of gems at Muzo. From the middle of the Seventeenth to the last years of the Nineteenth Century, this region of deep valleys and vast mountains remained untrodden. But little was done, for landslides, yellow fever, and malaria did much to hamper operations. A German syndicate which followed had small success as the war of 1914 interrupted their plans. An American company followed in 1919, called the Colombian Emerald Syndicate Ltd., afterwards called the Colom bian Emerald Development Corporation of New York. From 1925 to 1932, the Chivor-Somondoco mines were operated with some success by an American syndicate, and another contract by which a French firm marketed some stones was terminated in 1928. Now the Colombian Government has assumed sole control of the mines, selling direct to dealers. Stones may be shipped only under government seal, and very strict precautions against theft and illicit mining are taken. All rough emeralds found in Colombia are confiscated by the Government, although actually very few stones have been produced since 1940.

During part of 1934, the value of the production from the Muzo mines was given as being about $140,000 (£50,000). Most of the rough is now cut in the U.S.A., and since some 30 to 50 per cent by weight is lost in the production of a faceted stone of the step or emerald cut, good specimens must have been mined to amount to this figure. Early in 1934, a law was passed in Colombia which compelled all those who dealt in emeralds to register with the Government. Both at Chivor and at Muzo, the emerald-bearing rock consists of a series of layers of different sediments which are mainly bright gray strata of limestone, separated by layers of coal. Fissures in these layers have allowed various hot solutions to rise, and through these fissures various crystals have formed, among which are emeralds.

These vein-bearing cracks vary in length up to 200 feet and in breadth up to 8 inches. Emeralds are found in the shape of nests of crystals, and they are sometimes covered with limonite and other mixed minerals, such as albite and pyrites. The crystals, which are of the hexagonal prism form, are often of good quality and color. Occasionally, parti-colored stones occur.. The gem bearing area is a region of about 4,000 square miles, but the only mine at present being worked is the Muzo, which lies about 92 miles northwest of Bogota. The general method of mining is simple yet effective, most of the work being performed by Indians. Other mining centers are Coscuez and Somondoco (or Chivor).

These places are also situated at high altitudes and in most inac­cessible and rugged districts. The surrounding dense tropical jungle renders the mining of the precious mineral an arduous task; transport, except by mule, is almost impossible, and fevers still cause many casualties among the miners. The neighborhood forest is first cleared by cutting or by fire, and then a trench is dug, usually in the form of a V, with the Walls sloping at an angle of 45° or more. Water, obtained from reservoirs furnished by the Garagoa river, sweeps away the debris which collects during the cutting of the trench. As depth is increased, steps of about three feet in height are cut in the sloping sides and the stones searched for emeralds. Each site is worked by (i group of some 15 to 40 men under a native overseer.

The entire operations are under the charge of an engineer, and stringent regulations make the theft of rough stones almost impossible. For instance, if the work on a vein is uncompleted by the end of the day, it is covered with wet lime and sealed by the superin­tendent. The workers live on the spot in buildings which are provided for them, and they are under constant police supervision. There is some opportunity for thieving as the calcite veins are removed by hand before being sorted and washed. The precious stones are picked out and graded, and those from Muzo are sent to Bogota under government seal by mule. A normal output for one year would be about 800,000 carats, but most of this, of course, would be of small size and of poor quality. Since stones are now tax free, good profits have been made in recent years. The supply of good, but not fine, stones re­mains fairly steady, and there is little competition from other areas. The handworked system has also proved to be both the cheapest and the most effective. Open cut mining has now re­placed the former method of tunneling. But the working of these mines has always been somewhat spasmodic on account of diffi­culties with the local Government, with labor, and with climatic conditions. Since 1939, practically no stones have come from the Muzo district. As we have already noted, many Colombian stones are cut in America, where there is a good demand for the first qualities. Various grades of the rough are also sent to India, where they are cut. Jaipur is the center, and the Indian lapidaries are very skilful although they work with small, hand driven machines.

Stones are cut to the best advantage at a fraction of the cost which European lapidaries charge. Some poor material used to be sent to China for carving into small ornaments, but during the last few years, internal conditions in that country have made this kind of work difficult. Large, fine emeralds are exceedingly rare and obtain enormous prices. There are far fewer fine emeralds than fine diamonds in existence. In the Middle Ages, good stones were used in church cups and chalices, and they formed the principal ornaments in the crown of Charlemagne. A crown set with 453 emeralds and weighing 1,521 carats, the center stone being 45 carats, still exists. This is said to have been worn by Atahualpa, the Peruvian Inca. It was bought a few years ago by an American syndicate, by whom it is valued at about $4,500,000. Many fine old stones have been spoiled, from our point of view, by engraving on them verses from the Koran; others have been drilled for use as nose ornaments and carved as idols. Old stones show scratches due to wear, but these may be polished out if they are not too deep. Most of the rulers of the native states of India possess very val­uable family treasures, among which are almost priceless gem stones. The Nizam of Hyderabad is said to own scent bottles carved from diamonds, and some of the finest pearls, rubies, sap­phires, and emeralds are in his possession. The emerald cup of a Mogul emperor, which was found in Delhi in 1920, was sold for $16,800 (£6,000) in New York (Sept. 1932). This jewel is cut from a single emerald, one and a half inches long, and it is only a sample of the treasures which India still possesses.

The largest single crystal of emerald in the rough, known as the "Mont Vert," weighs 2,650 carats. It is of fine color, although badly flawed, and originates from the Urals. Its owner is Mr. A. Bradley Martin of Long Island, New York- Another large single emerald crystal belongs to the Duke of Devonshire, to whose fam­ily it was given by Dom Pedro of Brazil about a hundred years ago. It is nearly a regular hexagon in shape, about two inches in diameter and length. Its weight is about 1,347 carats, and al­though of good color, it is flawed with chipped corners and edges. This stone was shown at the Great Exhibition in London, in 1851, and lately at the Natural History Museum in Kensington. The finest cut stone is said to have once belonged to the late Czar of Russia. This weighed about 30 carats. Among other no­table stones in the Russian State Treasures are two emeralds weighing 174 carats and 153 carats. The latter is quite clear with no flaws, but it has a Russian inscription on its face. The collec­tion of Uralian emeralds includes one of 250 carats, and another beautiful stone of 136 carats is probably of South American ori­gin. In London, a fine crystal and also a fine cut stone is on view at the British Museum (Mineral Gallery). Since emerald is of such great value, it is naturally imitated in a variety of ways, and these are noted in the chapter describing imitation and synthetic stones. The production of synthetic em­eralds is a fairly recent discovery, and those now appearing on the market under the name of Chatham emeralds are a good re­production of the natural stone. They are made in all sizes and qualities, although many of the so-called synthetic emeralds are either synthetic green spinels or emerald glasses. It is emphasized that great care should be observed when considering emeralds of some value since synthetics may now be found in mounted jewelry. Their value would be less than one-tenth of that of the natural stone. The material in question is a true synthetic em­erald; it is made in the U.S.A. and marketed from Geneva and other centers. Various tests will distinguish it from the natural stone. A lower power microscope with a strong lens should be used to examine internal structure. Flotation in a heavy liquid of density 2.67 should be tried also, for in this the synthetic will probably float and the natural stone will sink. True emerald doublets are very seldom seen, but the so-called soude emerald is occasionally mounted in medium priced forms of jewelry. This is a thin piece of green glass which has been ce­mented between two thicker pieces of rock crystal. If viewed side­ways, the lines showing the joining edges of the layers will be seen. Internal air bubbles are often detectable, whilst the green color under a filter (such as the Chelsea color filter) will distin­guish this fake since natural stones would appear red. Lack of absorption bands is an additional discriminating feature, for un­der the spectroscope the emerald shows a broad band somewhat similar to ruby. The green and yellow parts of the spectrum are obscured, but the blue-green and blue are seen.

The word emerald comes to us from the Sanskrit word baraq, meaning "to flash." The Sanskrit marakatam from this source, added to asma, meaning "a stone," gives the Latin smaragdus, a term which approximates to the word for emerald in many differ­ent Romance languages. Our "emerald" is derived from the late French emeraude. The term emerald should be applied strictly to only the bright green beryl. Such names as Brazilian emerald, which is sometimes used for green tourmaline, Oriental emerald for green sapphire, Uralian emerald for green garnet, Lithium emerald for hiddenite, Copper emerald for dioptase, Cape emerald for prehnite, and African emerald for green fluorspar are both unnecessary and misleading.