Part 7 (1/2)
or pestle and mortar, easily obtained three hundred ounces of the precious metal. The unwelcome visitors stole two hundred ounces of the gold, a circ.u.mstance which obliged them to report their 'find' sooner than they would otherwise have done, fearing that, if they delayed, the thieves would do so instead, and claim the reward from the government.
On condition that they would not molest his mate during his absence, Mr Bayley agreed to say nothing about their having robbed him, and set out on his long ride to Southern Cross. He took with him five hundred and fifty-four ounces of gold with which to convince the Warden that his discovery was a genuine one. The field was declared open after his interview with the authorities.
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 l.u.s.tre 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 l.u.s.tre. 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 phosph.o.r.escent, 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.
[Ill.u.s.tration: Square-cut Brilliant.]
[Ill.u.s.tration: Round-cut Brilliant.]
[Ill.u.s.tration: Rose-cut Diamond.]
The art of cutting and polis.h.i.+ng 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 polis.h.i.+ng 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 fas.h.i.+onable, 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 151-1/2 carats are equal to one ounce troy.
India was formerly the only country which yielded diamonds in quant.i.ty, 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 G.o.davari 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 67-3/8 carats, was found near Wajra Karur, in the Bellary district, Madras. The stone was cut into a brilliant weighing 24-5/8 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 was.h.i.+ngs of the province of Minas Geraes was first detected. Diamonds occur not only in this province, but in Bahia, Goyaz, Matto Grosso, and Parana. 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, a.s.sociated 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 254-1/2 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 princ.i.p.al 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 288-3/8 carats, and yielded a fine pale yellow brilliant, known as the 'Stewart.'
[Ill.u.s.tration: 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 princ.i.p.al 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 a.s.sociated 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 princ.i.p.al 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 46-1/2 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 428-1/2 carats in the rough, and 228-1/2 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 969-1/2 carats (or about 6-1/2 oz.), and the following are its recorded dimensions: Length, 2-1/2 inches; greatest width, 2 inches; smallest width, 1-1/2 inches; extreme girth in width, 5-3/8 inches; extreme girth in length, 6-3/4 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 5-1/2 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 princ.i.p.al 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 p.r.o.nounced 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 23-3/4 carats, and yielded, when cut, a brilliant known as the 'Ou-i-nur,' which weighed, however, only 11-3/4 carats.
A few special diamonds, from their exceptional size or from the circ.u.mstances 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 pa.s.sed 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 peac.o.c.k adorning his famous peac.o.c.k 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 pa.s.sed to his unfortunate son, Shah Rokh, by whom it was ultimately given to Ahmed Shah, the founder of the Durani Afghan empire.