Chapter IX: "farewell, Mackrimmon!" (2)

Beautiful transparent beryls have been found among the granite hills of Oxford county in Maine, and the late Governor Lincoln nearly half a century ago possessed a splendid crystal which would have rivaled the superb prism found at Mouzzinskaia, and which the Russians value so highly. The extended and unexplored ledges of granite which rise from the shores of the ocean at Harpswell in Maine, and stretch north-westward for nearly a hundred miles, quite to the base of the White Mountain group, are not only rich in beryls, but they contain many of the rarest minerals known to the mineralogist. And perhaps there is no other field of equal extent in the country which offers to the mineralogist such a harvest of the rare and curious productions of the mineral kingdom.

At Haddam in Connecticut beautiful crystals of beryl have been discovered, and one of these, of fine green color, an inch in diameter and several inches in length, was preserved in the cabinet of Colonel Gibbs. Professor Silliman possessed another fine one, seven inches in length.

The mountains in Colorado have yielded some fine specimens. But the finest of the beryl species come from Russia. In the Ural Mountains the crystals are small, but of fine color; in the Altai Mountains they are very large and of a greenish blue; but in the granitic ledges of Odon Tchelon in Daouria, on the frontier of China, they are found in the greatest perfection. They occur on the summit of the mountain in irregular veins of micaceous and white indurated clay, and are greenish-yellow, pure pale green, greenish-blue and sky-blue. The chief matrix of the beryl all over the world is graphic granite, but it may occur in other rocks. The light green stones of Limoges in France appear in a vein of quartz traversing granite. At Royalston we observed them to spring seemingly from the felspar and project into smoky quartz, becoming more transparent as they advanced into the harder stone.

The beryl possesses the same crystalline form and specific gravity as the emerald, but its hardness (especially in the yellow varieties) is sometimes greater. The only perceptible difference in the two stones is in the color. Cleaveland thought that as the emerald and beryl had the same essential characters, they might gradually pass into each other; and Klaproth, finding the oxides of both chrome and iron in one specimen, was led to take the same view. The crystals of true emerald are almost always small (with the exception of those found in the Wald district in Siberia), whilst those of the beryl vary from a few grains to more than a ton in weight. The crystals of both are almost invariably regular hexahedral prisms, sometimes slightly modified. Those of the beryl we sometimes find quite flat, as though they had been compressed by force: then again they are acicular and of extraordinary length, considering their slender diameter. Sometimes their lateral faces are longitudinally striated, and as deeply as the tourmaline, so that the edges of the prism are rendered indistinct. Other crystals are curved, and some perforated in the axis like the tourmaline, so as to contain other minerals. Sometimes they are articulated like the pillars of basalt, and separated at some distance by the intervening quartz. These modified forms give rise to curious speculations as to their formation and origin. If we admit the action of fire (which is improbable), then the separation may be easily explained; but if we insist that they were deposited in the wet way and by slow process, how can we account for the dislocation? "By electricity," whispers a friend--"by telluric magnetism, that wonderful unexplained and mysterious force which has caused the grand geological changes of the globe, and is still at work."

No other gem has been counterfeited with such perfection as the emerald; and in fact it is utterly impossible to distinguish the artificial from the real gems by the aid of the eye alone: even the little flaws which lull the suspicions of the inexperienced are easily produced by a dexterous blow from the mallet of the skilled artisan. Not only emeralds, but most of the gems and precious stones, are now imitated with such consummate skill as to deceive the eye, and none but experts are aware of the extent to which these fictitious gems are worn in fashionable society, for oftentimes the wearers themselves imagine that they possess the real stones. There is not one in a hundred jewelers who is acquainted with the physical properties of the gems, and very few can distinguish the diamond from the white zircon or the white topaz, the emerald from the tourmaline of similar hue, the sapphire from iolite, or the topaz from the Bohemian yellow quartz. Jewelers are governed generally by sight, which they believe to be infallible, whilst hardness and specific gravity are the only sure tests.

Artificial gems rivaling in beauty of color the most brilliant and delicately tinted of the productions of Nature are now made at Paris and in other European cities. The establishments at Septmoncel in the Jura alone employ a thousand persons, and fabulous quantities of the glittering pastes are made there and sent to all parts of the world.

A fine specimen of prase when cut affords a fair imitation of the emerald. The green fluor-spar which Haüy called "emeraude de Carthagène" may also be substituted, but the application of the file detects the trick with ease. Some of the green tourmalines approach the emeralds in hue very closely, and by artificial light it is impossible to distinguish them from each other. Fragments of quartz may be stained by being steeped in green-colored tinctures. The Greeks stained quartz so like the real gem that Pliny exclaimed against the fraud while declining to tell how it was done. The Ancona rubies at the present day are made by plunging quartz into a hot tincture of cochineal, which penetrates the minute fissures of the rock.

But notwithstanding the high art reached by modern glass-makers, they are yet far behind the ancients in imitating the emerald in point of hardness and lustre. Many emerald pastes of Roman times still extant are with difficulty distinguished from the real gem, so much harder and lustrous are they than modern glass. The ancient Phoenician remains found in the island of Sardinia by Cavalier Cara in 1856 show fine color in their enamels and glass-works. The green pigment brought home from the ruins of Thebes by Mr. Wilkinson was shown by Dr. Ure to consist of blue glass in powder, with yellow ochre and colorless glass. From Greek inscriptions dating from the period of the Peloponnesian war we learn that there were signets of colored glass among the gems in the treasury of the Parthenon.

Of all the emerald imitations that have descended to us from antiquity, none are more remarkable, none more interesting to the antiquary and historian, than the famous Sacro Catino of the cathedral of Genoa. This celebrated relic is a glass dish or patera fourteen inches in width, five inches in depth and of the richest transparent green color, though disfigured by several flaws. It was bestowed upon the republic of Genoa by the Crusaders after the capture of Caesarea in 1101, and was regarded as an equivalent for a large sum of money due from the Christian army. It was traditionally believed to have been presented to King Solomon by the queen of Sheba, and afterward preserved in the Temple, and some accounts relate that it was used by Christ at the institution of the Lord's Supper. The Genoese received it with so much veneration and faith that twelve nobles were appointed to guard it, and it was exhibited but once a year, when a priest held it up in his hand to the view of the passing throng. The state in 1319, in a time of pressing need, pawned the holy relic for twelve hundred marks of gold (two hundred thousand dollars), and redeemed it with a promptness which proved its belief in the reality of the material as well as in its sanctity. And it is also related that the Jews, during a period of fifty years, lent the republic four million francs, holding the sacred relic as a pledge of security. Seven hundred years passed away, when Napoleon came, and as he swept down over Italy, gathering her art-treasures, he ordered the "Holy Grail" to be conveyed to Paris. It was deposited in the Cabinet of Antiquities in the Imperial Library, and the mineralogists quickly discovered it to be glass. It is due to the memory of Condamine to state that he was the first to doubt the material of the Sacro Catino, for, when examining it by lamplight in 1757, in the presence of the princes Corsini, he observed none of the cracks, clouds and specks common to emeralds, but detected little bubbles of air. In 1815 the Allies ordered its return to the cathedral of Genoa. During this journey the beautiful relic was broken, but its fragments were restored by a skillful artisan, and it is now supported upon a tripod, the fragments being held together by a band of gold filigree. This remarkable object of antiquity, which is of extraordinary beauty of material and workmanship, furnishes a theme over which the antiquaries love to muse and wrangle.

Another of the antique monster emeralds, weighing twenty-nine pounds, was presented to the abbey of Reichenau near Constance by Charlemagne. Beckman has also detected this precious relic to be glass. And probably the great emerald of two pounds weight brought home from the Holy Land by one of the dukes of Austria, and now deposited in the collection at Vienna, is of the same material. The hardness of our glass is yet far inferior to that of the ancients, and even the ruby lustre of the potters of Umbria, which was so precious to the dilettanti of the Cinque Cento period, has not been recovered.

The emerald has been a subject of controversy among the chemists and mineralogists, and its character, especially the cause of its beautiful color, is not clearly defined even at the present day. But that distinguished chemist, Professor Lewy of Paris, seems to offer, thus far, the most correct and plausible theory. Ten years ago he boldly asserted that the hue is not due to the oxide of chromium, and with this opinion he confronted such eminent men as Vauquelin, Klaproth and others of high rank in the scientific world. Not content with his researches in his laboratory in Paris, he resolutely crossed the ocean and sought the emerald in its parent ledges in the lofty table-lands of New Granada. Here he obtained new information of a geological character which goes far to strengthen his position. The experiments of M. Lewy indicate, if they do not prove, that the coloring matter of the emerald is organic, and readily destroyed by heat, which would not be the case if it was due to the oxide of chromium. All my own fire-tests with the Granada emerald corroborate the views of M. Lewy, for in every instance the gem lost its hue when submitted to a red heat.

Nevertheless, the recent researches of Wöhler and Rose give negative results. These experienced chemists kept an emerald at the temperature of melted copper for an hour, and found that, although the stone had become opaque, the color was not affected. They therefore considered the oxide of chromium to be the coloring agent, without, however, denying the presence of organic matter. The amount of the oxide of chromium found by many chemists varies from one to two per cent., while Lewy and others found it in a quantity so small as to be inappreciable, and too minute to be weighed.

Before the ordinary blowpipe the emerald passes rapidly into a whitish vesicular glass, and with borax it forms a fine green glass, while its sub-species, the beryl, changes into a colorless bead: with salt of phosphorus it slowly dissolves, leaving a silicious skeleton.[A]

M. Lewy visited the mines at Muzo in Granada, and from the results of his analyses, together with the fact of finding emeralds in conjunction with the presence of fossil shells in the limestone in which they occur, he arrived at the conclusion that they have been formed in the wet way--deposited from a chemical solution. He also found that when extracted they are so soft and fragile that the largest and finest fragments can be reduced to powder by merely rubbing them between the fingers, and the crystals often crack and fall to pieces after being removed from the mine, apparently from loss of water. Consequently, when the emeralds are first extracted they are laid aside carefully for a few days until the water is evaporated.

This statement relative to the softness of the gem and its subsequent hardening has been met with a shout of derision from some of the gem-seekers--none louder than that of Barbot, the retired jeweler. Barbot seems to forget that the rock of which his own house in Paris is constructed undergoes the same change after being removed from the deep quarries in the catacombs under the city. This phenomenon is observed with many rocks. Flints acquire additional toughness by the evaporation of water contained in them. The steatite of St. Anthony's Falls grows harder on exposure, and other minerals when quarried from considerable depths become firmer on exposure to the action of the air. Observations of this kind led Kuhlman to investigate the cause, and he believes that the hardening of rocks is not owing solely to the evaporation of quarry-water, but that it depends upon the tendency which all earthy matters possess to undergo a spontaneous crystallization by slow dessication, which commences the moment the rock is exposed to the air.

The coloring matter of the emerald seems to be derived from the decomposition of the remains of animals who have lived in a bygone age, and whose remains are now found fossilized in the rock which forms the matrix of the gem. This rock in Granada is a black limestone, with white veins containing ammonites. Specimens of these rocks exhibiting fragments of emeralds _in situ_, and also ammonites, are to be seen in the mineralogical gallery of the Jardin des Plantes in Paris. Lewy believes that the beautiful tint of these gems is produced by an organic substance, which he considers to be a carburet of hydrogen, similar to that called chlorophyll, which constitutes the coloring matter of the leaves of plants; and he has shown that the emeralds of the darkest hue, which contain the greatest amount of organic matter, lose their color completely at a low red heat, and become opaque and white; while minerals and pastes which are well known to be colored by chromium, like the green garnets (the lime-chrome garnets) of Siberia, are unchanged in hue by the action of heat.

Since the time of the Spanish Conquest, New Granada has furnished the world with the most of its emeralds. The most famous mines are at Muzo, in the valley of Tunca, between the mountains of New Granada and Popayan, about seventy-five miles from Santa Fé de Bogota, where every rock, it is said, contains an emerald. At present the supply of emeralds is very limited, owing to restrictions on trade and want of capital and energy in mining operations.

Blue as well as green emeralds are found in the Cordillera of the Cubillari. The Esmeraldas mines in Equador are said to have been worked successfully at one period by the Jesuits. The Peruvians obtained many emeralds from the barren district of Atacama, and in the times of the Conquest there were quarries on the River of Emeralds near Barbacoas.

Emeralds are found in Siberia, and some of the localities may have furnished to the ancients the Scythian gems which Pliny and others mention. In the Wald district magnificent crystals have been found embedded in mica-slate. One of these--a twin-crystal, now in the Imperial Cabinet at St. Petersburg--is seven inches long, four inches broad, and weighs four and a half pounds. There is another mass in the same collection which measures fourteen inches long by twelve broad and five thick, weighing sixteen and three-quarter pounds troy. This group shows twenty crystals from a half inch to five inches long, and from one to two inches broad. They were discovered by a peasant cutting wood near the summit of the mountain. His eye was attracted by the lustrous sparkling amongst the decomposed mica and where the ground had been exposed by the uprooting of a tree by the violence of the wind. He collected a number of the crystals, and brought them to Katharineburg and showed them to M. Kokawin, who recognized them and sent them to St. Petersburg, where they were critically examined by Van Worth and pronounced to be emeralds. One of these crystals was presented by the emperor to Humboldt when he visited St. Petersburg, and it is now deposited in the Berlin collection. Quite a number of emeralds are now brought from the Siberian localities, and it is believed that enterprise and capital would produce a large supply of the gem.[B]

The supply of emeralds from South America is very limited, and may be ascribed to want of skillful mining, as well as to climate, the political condition of the country and the indolence of its inhabitants. The localities cannot be exhausted, for they are too numerous and extensive. The elevated regions in Granada admit of scientific exploration by Europeans, and at the present day the only emerald-mining operations conducted in South America have been prosecuted near Santa Fé de Bogota by a French company, which has paid the government fourteen thousand dollars yearly for the right of mining, all the emeralds obtained being sent to Paris to be cut by the lapidaries of that city.

In the Atacama districts, and along the banks of the River of Emeralds, the physical obstructions are difficult to overcome, and pestilential diseases of malignant character forbid the long sojourn of the European. Yet the introduction of Chinese labor may prove successful and highly remunerative, since the coolie reared among the jungles and rice-swamps of Southern China is quite as exempt from malarial fevers as the negro.

The price of the emerald has no fixed and extended scale, like that of the diamond, and the fluctuations of its value during the past three centuries form an interesting chapter in the history of gems.

In the time of Dutens (1777) the price of small stones of the first quality was one louis the carat; one and a half carats, five louis; two carats, ten louis; and beyond this weight no rule of value could be established. In De Boot's day (1600) emeralds were so plenty as to be worth only a quarter as much as the diamond. The markets were glutted with the frequent importations from Peru, and thirteen years before the above-mentioned period one vessel brought from South America two hundred and three pounds of fine emeralds, worth at the present valuation more than seven millions of dollars. At the beginning of this century, according to Caire, they were worth no more than twenty-four francs (or about five dollars) the carat, and for a long time antecedent to 1850 they were valued at only fifteen dollars the carat. Since this period they have become very rare, and their valuation has advanced enormously. In fact, the value of the emerald now exceeds that of the diamond, and is rapidly approaching the ratio fixed by Benevenuto Cellini in the middle of the sixteenth century, which rated the emerald at four times, and the ruby at eight times, the value of the diamond. Perfect stones (the emerald is exceedingly liable to flaw, the beryl is more free, and the green sapphire is rarely impaired by fissures or cracks) of one carat in weight are worth at the present day two hundred dollars in gold. Perfect gems of two carats weight will command five hundred dollars in gold, while larger stones are sold at extravagant prices.

Most of our aqua-marinas come from Brazil and Siberia, and small stones are sold at trifling prices. Some of them, however, when perfect and of fine color, command fabulous sums. The superb little beryl found at Mouzzinskaia is valued by the Russians at the enormous sum of one hundred and twenty thousand dollars, although the crystal weighs but little more than one ounce. Another rough prism preserved in the Museum at Paris, and weighing less than one hundred grains, has received the tempting offer of fifteen thousand francs.

A.C. HAMLIN, M.D.

[Footnote A: A curious result happened to the elder Silliman when experimenting with a Peruvian emerald before the compound blowpipe. The reducing flame instantly melted it into a transparent green globule. Perhaps the intense heat of this all-powerful flame, which reduces even the diamond, recalled the colors which disappear at a lower temperature. But this could not be done if the color was due to organic matter, which is annihilated or modified beyond recall by combustion.]

[Footnote B: Several of the natural crystals of the Siberian emeralds of large size and beautiful color are now to be seen in the valuable and choice collections of Messrs. Clay and William S. Vaux of Philadelphia.]

BERRYTOWN.