DIAMONDS.
The diamond is a natural form of crystallised carbon, highly valued as a precious stone, but of much less value than the ruby. The lustre of the diamond is peculiar to itself, and hence termed 'adamantine.' In a natural condition, however, the surface often presents a dull, lead-gray, semi-metallic lustre. The high refractive and dispersive powers of the diamond produce, when the stone is judiciously cut, a brilliancy and 'fire' unequalled by any other stone. A large proportion of the incident light is in a well-cut diamond reflected from the inner surface of the stone. The diamond, especially when coloured, is highly phosphorescent, that is to say, after exposure to brilliant illumination it emits the rays which it has absorbed, and thus becomes self-luminous in the dark. Its excessive hardness serves to distinguish the diamond from other gem-stones: any stone which readily scratches ruby and sapphire must be a diamond. Notwithstanding its hardness the diamond is brittle, and hence the absurdity of the ancient test which professed to distinguish the diamond by its withstanding a heavy blow struck by a hammer when placed on an anvil.
In recent years, highly refined researches on this subject have been made by Dumas, Stas, Roscoe, and Friedel, all tending to prove that the diamond is practically pure carbon. Chemists have generally experimented, for the sake of economy, with impure specimens, and have thus obtained on combustion a considerable amount of ash, the nature of which has not been well ascertained. It has been shown, however, that the purer the diamond the smaller is the proportion of ash left on its combustion.
Square-cut Brilliant.
Round-cut Brilliant.
Rose-cut Diamond.
The art of cutting and polishing the diamond is said to have been discovered in 1456 by Louis de Berguem of Bruges. As now practised, the stone is first, if necessary, cleaved or split, and then 'bruted' or rubbed into shape. The faces of the stone thus 'cut' are ground and polished on flat metal discs, fed with diamond dust and oil, and revolving with great rapidity by steam-power. Antwerp comes first, then Amsterdam as the chief home of this industry, and the trade is chiefly in the hands of Jews; but diamond cutting and polishing are also now extensively carried on in London, Antwerp, &c. The common form of the diamond is either the brilliant or the rose cut. The brilliant resembles two truncated cones, base to base, the edge of the junction being called the girdle, the large plane on the top is the table, and the small face at the base the culet; the sides are covered with symmetrical facets. The rose has a flat base, with sides formed of rows of triangular facets rising as a low pyramid or hemisphere; but this form of diamond is daily becoming less fashionable, and is therefore of comparatively little value.
Although the term 'carat' is applied to diamonds as well as to gold, it does not mean the same thing. Used with regard to the metal, it expresses quality or fineness—24-carat being pure gold; and 22-carat equal to coined gold. But applied to the diamond, carat means actual weight, and 151½ carats are equal to one ounce troy.
India was formerly the only country which yielded diamonds in quantity, and thence were obtained all the great historical stones of antiquity. The chief diamond-producing districts are those in the Madras Presidency, on the Kistna and Godavari rivers, commonly though improperly termed the Golconda region; in the Central Provinces, including the mines of Sumbulpur; and in Bundelkhand, where the Panna mines are situated.
At present the diamond production of India is insignificant. It is notable, however, that in 1881 a fine diamond, weighing 67⅜ carats, was found near Wajra Karur, in the Bellary district, Madras. The stone was cut into a brilliant weighing 24⅝ carats, and is known as the 'Gor-do-Norr.'
Brazil was not regarded as a diamond-yielding country until 1727, when the true nature of certain crystals found in the gold washings of the province of Minas Geraes was first detected. Diamonds occur not only in this province, but in Bahia, Goyaz, Matto Grosso, and Paraná. The geological conditions under which the mineral occurs have of late years been carefully studied by Professors Derby, Gorceix, and Chatrian. The diamonds are found in the sands and gravels of river-beds, associated with alluvial gold, specular iron ore, rutile, anatase, topaz, and tourmaline. In 1853 an extraordinary diamond was found by a negress in the river Bogagem, in Minas Geraes. It weighed 254½ carats, and was cut into a brilliant of perfect water, weighing 125 carats. This brilliant, known as the 'Star of the South,' was sold to the Gaikwar of Baroda for £80,000.
Both the Indian and the Brazilian diamond-fields have of late years been eclipsed by the remarkable discoveries of South Africa. Although it was known in the last century that diamonds occurred in certain parts of South Africa, the fact was forgotten, and when in 1867 they were found near Hopetown, the discovery came upon the world as a surprise. A traveller named O'Reilly had rested himself at a farm in the Hopetown district, when his host, a man named Niekerk, brought him some nice-looking stones which he had got from the river. O'Reilly, when examining the pebbles, saw a diamond, which afterwards realised £500. Niekerk afterwards bought a diamond from a native for £400 which realised £10,000. The principal mines are situated in Griqualand West, but diamonds are also worked in the Orange River Free State, as at Jagersfontein. The stones were first procured from the 'river diggings' in the Vaal and Orange rivers. These sources have occasionally yielded large stones; one found in 1872 at Waldeck's Plant on the Vaal weighed 288⅜ carats, and yielded a fine pale yellow brilliant, known as the 'Stewart.'
Kimberley Diamond-mine.
It was soon found that the diamonds of South Africa were not confined to the river gravels, and 'dry diggings' came to be established in the so-called 'pans.' The principal mines are those of Kimberley, De Beer's, Du Toit's Pan, and Bultfontein. The land here, previously worth only a few pence per acre, soon rose to a fabulous price. At these localities the diamonds occur in a serpentinous breccia, filling pipes or 'chimneys,' generally regarded as volcanic ducts, which rise from unknown depths and burst through the surrounding shales. The 'blue ground,' or volcanic breccia containing fragments of various rocks cemented by a serpentinous paste, becomes altered by meteoric agents as it approaches the surface, and is converted into 'yellow earth.' At Kimberley the neighbouring schists, or 'reefs,' are associated with sheets of a basaltic rock, which are pierced by the pipes. About 2000 white men are employed in the industry, and about 4000 blacks, who earn, on an average, about £3 a week. In the year 1887 the production of the principal mines was over £4,000,000. The production for 1894 was somewhat less, while the total value of diamonds exported from 1867 to 1894 was about £70,000,000.
The great number of large stones found in the mines of South Africa, as compared with those of India and Brazil, is a striking peculiarity. In the earliest days of African mining a diamond of about 83 carats was obtained from a Boer. This stone, when cut, yielded a splendid colourless brilliant of 46½ carats, known as the 'Star of South Africa,' or as the 'Dudley,' since it afterwards became the property of the Countess of Dudley, at a cost of £25,000. Some of the African stones are 'off coloured'—that is, of pale yellow or brown tints; but a large gem of singular purity was found at Kimberley in 1880. This is the famous 'blue-white' diamond of 150 carats, known from the name of its possessor as the 'Porter Rhodes.' At the De Beer's Mine was found, in 1889, the famous stone which was shown at the Paris Exposition. It weighed 428½ carats in the rough, and 228½ carats when cut. It measured one inch and seven-eighths in greatest length, and was about an inch and a half square.
Even larger than this remarkable stone is a diamond found in the Jagersfontein Mine in 1893, and named the 'Jagersfontein Excelsior.' This is now the largest and most valuable diamond in the world. It is of blue-white colour, very fine quality, and measures three inches at the thickest part. The gross weight of this unique stone was no less than 969½ carats (or about 6½ oz.), and the following are its recorded dimensions: Length, 2½ inches; greatest width, 2 inches; smallest width, 1½ inches; extreme girth in width, 5⅜ inches; extreme girth in length, 6¾ inches. It is impossible to say what is the value of so phenomenal a gem. We do not know that an estimate has been even attempted; but it may easily be half a million if the cutting is successful. The diamond has, however, a black flaw in the centre. It is the property of a syndicate of London diamond merchants. The native who found it evaded the overseer, and ran to headquarters to secure the reward, which took the form of £100 in gold and a horse and cart.
Previous to this discovery, the most famous of the African diamonds was, perhaps, the 'Pam' or 'Jagersfontein' stone, not so much from its size, as because the Queen had ordered it to be sent to Osborne for her inspection with a view to purchase, when the untimely death of the Duke of Clarence put an end to the negotiations. The 'Pam' is only of 55 carats now; but it weighed 112 carats before being cut, and is a stone of remarkable purity and beauty. Its present value is computed at about twenty-five thousand pounds sterling.
The most valuable diamond in the world is (if it is a diamond) the famous 'Braganza' gem belonging to Portugal. It weighed in the rough state 1680 carats, and was valued at upwards of 5½ millions sterling.
It has long been known that diamonds occur in Australia, but hitherto the Australian stones have been all of small size, and it is notable that these are much more difficult to cut, being harder than other diamonds. Although Victoria and South Australia have occasionally yielded diamonds, it is New South Wales that has been the principal producer. The chief diamond localities have been near Mudgee, on the Cudjegong River, and near Bingera, on the river Horton.
Borneo also yields diamonds. The stone known as the 'Matan' is said to have been found in 1787 in the Landak mines, near the west coast of Borneo. It is described as being an egg-shaped stone, indented on one side, and weighing, in its uncut state, 367 carats. Great doubt, however, exists as to the genuineness of this stone, and the Dutch experts who examined it a few years ago pronounced it to be simply rock-crystal. Among other diamond localities may be mentioned the Ural Mountains and several of the United States. The largest diamond yet recorded from North America was found at Manchester, Chesterfield county, Virginia. It weighed 23¾ carats, and yielded, when cut, a brilliant known as the 'Ou-i-nur,' which weighed, however, only 11¾ carats.
A few special diamonds, from their exceptional size or from the circumstances of their history, deserve notice. Of all the great diamonds, the 'Koh-i-nur' is perhaps the most interesting. While tradition carries it back to legendary times, it is known from history that the Sultan Ala-ed-din in 1304 acquired this gem on the defeat of the Rajah of Malwa, whose family had possessed it for many generations. In 1526 it passed by conquest to Humaiun, the son of Sultan Baber. When Aurungzebe subsequently possessed this stone, he used it as one of the eyes of the peacock adorning his famous peacock throne. On the conquest of Mohammed Shah by Nadir Shah in 1739, the great diamond was not found among the Delhi treasures, but learning that Mohammed carried it concealed in his turban, Nadir, on the grand ceremony of reinstating the Mogul emperor on the throne at the conclusion of peace, offered to exchange turbans, in token of reconciliation, and by this ruse obtained possession of the gem. It was when Nadir first saw the diamond on unfolding the turban, that he exclaimed 'Koh-i-nur,' or 'Mountain of Light,' the name by which the gem has ever since been known. At Nadir's death it passed to his unfortunate son, Shah Rokh, by whom it was ultimately given to Ahmed Shah, the founder of the Durani Afghan empire. By Ahmed it was bequeathed to his son, Taimur Shah; and from his descendants it passed, after a series of romantic incidents, to Runjit-Singh. On the death of Runjit, in 1839, the diamond was preserved in the treasury of Lahore, and on the annexation of the Punjab by the British in 1849, when the property of the state was confiscated to the East India Company, it was stipulated that the Koh-i-nur should be presented to the Queen of England. It was consequently taken in charge by Lord Dalhousie, who sent it to England in 1850. After the Great Exhibition of 1851, where it had been exhibited, it was injudiciously re-cut in London by Voorsanger, a skilful workman from Messrs Coster's factory at Amsterdam. The re-cutting occupied 38 days of 12 hours each, and the weight of the stone was reduced from 1861⁄16 to 1061⁄16 carats. The form is that of a shallow brilliant, too thin to display much fire. According to Lady Burton, it is believed to bring ill-luck to its possessor.
The 'Nizam' is the name of a stone said to have been found in the once famous diamond-mines of Golconda. Sir William Hunter, however, gives us to understand that there were really no diamond-mines at Golconda, and that the place won its name by cutting the stones found on the eastern borders of the Nizam's territory, and on a ridge of sandstone running down to the rivers Kistna and Godavery, in the Madras Presidency. However that may have been, both regions are now unproductive of valuable stones. The 'Nizam' diamond is said to weigh 340 carats, and to be worth £200,000; but we are unable to verify the figures.
The 'Great Table' is another Indian diamond, the present whereabouts of which is not known. It is said to weigh 242½ carats, and that 500,000 rupees (or at par, £50,000) was once refused for it. The 'Great Table' is sometimes known as 'Tavernier's' diamond. It was the first blue diamond ever seen in Europe, and was brought, in 1642, from India by Tavernier. It was sold to Louis XIV. in 1668, and was described then as of a beautiful violet colour; but it was flat and badly cut. At what date it was re-cut we know not, but, as possessed by Louis Le Grand, it weighed only 67½ carats. It was seized during the Revolution, and was placed in the Garde Meuble; but it disappeared, and has not been traced since. Some fifty years later, Mr Henry Hope purchased a blue diamond weighing some 44½ carats (now known as the 'Hope' diamond), which it was conjectured may have been part of the 'Great Table.' It is preserved in the Green Vaults, Dresden, and is regarded as one of the most superb coloured diamonds known.
Another famous Indian diamond is the 'Great Mogul,' which appears to have been found about 1650, in the Kollur mine, on the Kistna. It was seen by the French jeweller Tavernier at the court of Aurungzebe in 1665, and is described as a round white rose-cut stone of 280 carats. Its subsequent history is unknown, and it is probable that at the sacking of Delhi by Nadir Shah in 1739 it was stolen and broken up. Some authorities have sought to identify the Great Mogul with the Koh-i-nur, and others with the Orloff.
Some of the Principal Diamonds of the World:
a, Great Mogul; b, Star of the South; c, Koh-i-nur; d, Regent; e, Orloff.
All actual size.
The 'Orloff' is an Indian stone which was purchased at Amsterdam in 1776 by Prince Orloff for Catharine II. of Russia. The stone at one time formed the eye of an idol in a temple in the island of Seringham, in Mysore, whence it is said to have been stolen by a French soldier, who sold it to an English trader for £2000. The Englishman brought it home, and sold it for £12,000 to a Jew, who passed it on at a profit to an Armenian merchant. From the Armenian it was acquired, either by Catharine of Russia, or, for her, by one of her admirers, for £90,000 and a pension. It is now valued at £100,000. It weighs 193 carats, is about the size of a pigeon's egg, and is mounted in the imperial sceptre of the Czar.
Other famous stones are: The 'Austrian Yellow,' belonging to the crown of Austria, weighing 76½ carats, and valued at £50,000; the 'Cumberland,' belonging to the crown of Hanover, weighing 32 carats, and worth at least £10,000; the 'English Dresden,' belonging to the Gaikwár of Baroda, weighing 76½ carats, and valued at £40,000; the 'Nassak'—which the Marquis of Westminster wore on the hilt of his sword at the birthday ceremonial immediately after the Queen's accession—which weighs 78½ carats, and is valued at £30,000.
The 'Regent' is a famous diamond preserved among the national jewels in Paris. It was found in 1701, at the Parteal mines, on the Kistna, by a slave, who escaped with it to the coast, where he sold it to an English skipper, by whom he was afterwards treacherously killed. Thomas Pitt, grandfather of the first Earl of Chatham, at that time governor of Fort St George, purchased the stone, and had it re-cut in London, whence it is often known as the 'Pitt.' Its original weight was 410 carats, but it was reduced in cutting to 136¾; the result, however, was a brilliant of fine water and excellent proportions. Pitt sold it in 1717, through the financier John Law, to the Duke of Orleans, then Regent of France during the minority of Louis XV. The price paid was £135,000, and its value has since been estimated at £480,000. The stone is now among the French jewels in the Museum of Paris.
The large 'Sancy' is an historical diamond, about which many contradictory stories have been told. It appears that the Sancy was an Indian stone, purchased about 1570 by M. de Sancy, French ambassador at Constantinople. It passed temporarily into the possession of Henry III. and Henry IV. of France, and was eventually sold by Sancy to Queen Elizabeth of England. By James II. it was disposed of to Louis XIV., about 1695, for £25,000. At the beginning of the 19th century it passed to the Demidoff family in Russia, and by them it was sold in 1865 to Sir Jamsetjee Jeejeebhoy. In 1889 it was again in the market, the price asked being £20,000.
The Russian diamond, 'Moon of Mountains,' is set in the imperial sceptre, weighs 120 carats, and is valued at 450,000 roubles, or, say, about £75,000. The 'Mountain of Splendour,' belonging to the Shah of Persia, weighs 135 carats, and is valued at £145,000. In the Persian regalia there is said to be another diamond, called the 'Abbas Mirza,' weighing 130 carats, and worth £90,000.