The diamond industry is represented, at the Champ de Mars: by the Pavilion of the Cape mines, near the rue du Caire; by the Dutch cutter's workshop at the foot of the Eiffel Tower; by the Belgian cutter's workshop in the machine gallery, and by the main showcases of the jewellery section of the Palais central.
The Cape of Good Hope pavilion introduces us to the various operations of a diamond mine. We see the wagons used to transport the diamond soil, and the machines used to raise it to the ground.
We learn that the diamond soil is too hard when it has just been extracted to be able to separate the diamonds from it, and that it must first be spread out on flora, where it is watered at the same time as it is exposed to the sun, so that it disintegrates. The earth that has undergone this preparation is washed. The blue earth, of which a bag is washed every day from half past three to five o'clock in the pavilion at the Cape of Good Hope, is real blue diamond earth, of which one hundred thousand kilograms have been brought to Paris. The machine which is working before the eyes of the public is intended for the mines of the Cape.
After washing, when the gravel is separated, it is sorted in front of the visitors, who can follow the discovery of each diamond that falls under the hand of the workers.
The sixteenth-century Dutch house at the foot of the Eiffel Tower, with its authentic style and elegant construction of pink brick, with Delft tiles around the windows, contains a whole diamond-cutting plant such as is practised in this country, where the Amsterdam merchants employ no less than five hundred steam-driven millstones.
In this Dutch house there is a very fine collection of rough and cut diamonds, worth more than two million, and alongside the modern equipment there is displayed, as a historical document, one of the millstones used in the fifteenth century. To turn it, two men are needed, who replace each other every ten minutes, and the cost of their days is currently sufficient to maintain six steam millstones, each of which makes two thousand four hundred revolutions per minute.
In the workshop which operates in this pavilion, under the eyes of the public, one can imagine approximately those of the large factories.
Among the workmen whose duty it is to take the stone in the state in which it has been extracted from the mine, and to transform it into the pink and shiny appearance we see in the sparkling jewellers' sets, are the splitter, the cutter and the polisher.
The splitter makes a notch in the stone, which is fixed, by a very hard putty, at the end of a small stick, and, with the help of a sharp blade which he places in this notch, he splits the stone by striking the blade with an iron rod which serves as a hammer. The fragments are collected and classified in drawers, according to their size, and great skill is required to handle them, for they are sometimes so small that it takes a thousand of them to make a carat. However tiny they may be, they all have to be cut.
The cutter also holds the diamond at the end of a stick and wears it down by rubbing it against another diamond. He has to develop great muscular strength for this work, which is quite hard, and he is obliged to hold the joints of his hand with a tight-fitting leather glove. This worker has a certain responsibility and must be trusted. It is he who often decides whether the stone in his hands is to be cut to a shine or whether it is to be returned to the splitters to be divided into fragments and cut into a rose.
He must also, and this is not the least delicate point, judge what shape he will give the diamond, according to its layout and colour. He must combine his cut in such a way as to give it as much weight as possible, taking care that the defects can be removed by polishing, and drawing the facets in such a way as to have angles likely to lend themselves well to the refraction of the light and to produce beautiful fires.
But the most important part of this work is to find the meaning of the diamond. It is only in this direction that the facets can be worn, and the worker must start cutting the stone so that he can take all the facets in the direction.
The polishing is done by means of the steam wheels we have already mentioned, the rubbing part of which is coated with a paste made of oil and diamond powder. This powder, which is sometimes worth twelve francs a carat, i.e. sixty thousand francs a kilogramme, comes from the dust of the splitting and jewellery industry, which is ground in a mortar; it also comes from the edge, or unsharp diamond, and from the carbon, or black diamond, which is also ground and which can only be used for this purpose.
The diamond is fixed to the end of a rod which is itself held between the jaws of heavy iron clamps, and in this way the facet to be polished is held firmly against the rubbing part of the grinding wheel.
There is still a very conspicuous Belgian cutter's shop in the Palais des Machines; but a few words should be said about the Imperial, which is exhibited in the jewellery section, and which was the largest diamond known in Europe before the recent discovery of the one now on display at the Cape Town pavilion, weighing 228 carats. The Imperial weighs 180 carats, while the Regent weighs only 136 and the Kohinoor 106.
The Imperial was cut in Amsterdam under the direction and supervision of a committee of three of that city's leading lapidaries; the Queen of Holland was present when the first facet was applied. It took eighteen months to finish it completely. Its original weight, in its raw state, was 457 carats; to give it a pleasing shape, a piece of 45 carats was detached from it, which, cut itself, provided a brilliant of 20 carats.
Such is, in a few lines, the history of the diamond, which is treated, as one can see, in a very complete way at the Universal Exhibition.
© L'Exposition Universelle de 1889 - Louis Rousselet - 1890