Originally diamonds were preserved in their crystalline forms. But about 1300 A.D. in Europe, and perhaps earlier still in India, the art of polishing and shaping them seems to have been practised, and it was gradually perfected in the course of the ensuing centuries. Such an octah edral diamond set in a gold ring was found on the hand of Charlemagne at his tomb in Aix-la chapelle. The invention of the cutting of regu lar facets by polishing the diamond on a rotating disk covered with diamond dust has been commonly attributed to Lodowyk van Berghern of Bruges, in the latter part of the 15th century. These circular discs, about 30 centimetres in diameter, are of soft steel covered with diamond dust and.oil, and made to revolve at 3,000 revolu tions a minute. This gives the diamonds the artistic smooth surfaces and sharply defined edges. They are secured in a fusible metal dop or holder, held by a metal clamp to the wheel. The process is slow and tedious, and requires great skill to produce fine results. Until thirty years ago Amsterdam was the great dia mond-cutting centre of the world, but the finest cutting is also done in the United States, and in a great measure by machinery. As to the cutting process: Diamonds are, first, cleaved; that is, along the line of cleavage of the stone a tiny cut is made by scratching the stone with another diamond at the point where it is de sired to cleave it, then a dull knife-edge is placed in the cut, and a sharp blow will separate the stone on a cleavage plane. More recently, they are sawed with thin circular blades of phosphor-bronze charged with diamond dust and oil. Secondly, diamonds are cut by rub bing two diamonds together ("diamond cut diamond," as the old adage says), the stones being cemented with shellac to two pieces of wood or handles which are held in the hands, and rubbed together till they are of the desired form. This also has been super seded partly by an American machine. The diamond-cutting trade is carried on by 8,000 cutters and over 30,000 people are employed in preparing and setting the gems. A "rose° diamond is one which is quite flat under neath, with its upper part cut into 12 or more little faces or facets, usually triangles, the uppermost of which terminates in a point. A "table" diamond is one which has a large rectangular face on the top, surrounded by four lesser rectangles. A "brilliant" diamond is one which is cut in faces both at top and bottom, including the table at the top and the culet at the bottom; there are 32 faces on the to above the girdle, and 24 on the back, 58 in all. Sometimes eight more facets are added making 64 in all. The greatest amount of brilliancy and beauty is developed in the diamond by the "brilliant cut"; 98 per cent of all modern dia monds are cut in this form. Very few are at present "rose-cut" or "table-cut," though the rose-cut has been more or less in vogue from the 17th century; the table-cut was favored during the 15th and 16th centuries.
Some of the square or oblong diamonds are brilliant-cut with pointed facets as on the other diamonds; but there is another type of cutting known as the "emerald cut," in which there are generally three rows of gallery — or de gree-cutting, as it is termed—above the girdle, and they are degree-cut in the back. The brio tette is a stone that is pear-shape, heart-shape, or irregular shape, and is covered entirely with minute facets. The 'layette, or. marquise, are ohovate-shaped, brilliant-cut diamonds. The cut is adapted to the color of the stone.
Diamond cutters vary as to the angle of the dome or the pavilion of the diamond. When measured from the table over the edge to the girdle they vary from 35 degrees to 38 degrees; when measured from the culet over the side to the girdle, from 40 degrees to 45 degrees, al though generally 35 degrees for the top and 40 degrees for the back are the accepted measurements.
Nearly all diamonds are cut in the brilliant form. This was first used in France in the 17th century, under the influence and possibly at the suggestion of Cardinal Mazarin, who had a wonderful collection of diamonds which he be queathed to the French Crown in 1661. Two of
these Mazarins were sold at the sale of. the French Crown jewels in 1887.
The combustibility of diamonds was proved in 1694 by Averani and Targioni with the aid of burning glasses. That diamonds turned to car, borne acid when burned was proved by Lavoi sier in 1772. Many curious superstitions are connected with the diamond. It was supposed to show phenomena of sympathy and antipathy. It was fallaciously believed that the diamond, which resisted the two most powerful things in nature, iron and fire, might be dissolved by the blood of a goat; nevertheless, it could not be destroyed by being struck on an anvil, etc. It was believed also to show a curious rivalry with the magnet, to strengthen poisons, and sometimes to drive away madness.
That the diamond was known to the an cients is problematical; at most, occasional ex amples may have been brought to the Grmco Roman world about the beginning of our era. Two diamonds are mentioned by Castellani as being set in the eyes of an antique statue, but even this determination is doubtful. Therefore we may safely say that when the Prophet Jere miah speaks of diamonds under the name of Shamir as tools for engraving, and when Ezekiel and Zechariah compare the stubborn ness of the Israelites to the diamond, they refer to corundum. The same is true in almost all cases when the Greek and Latin writers allude to the adamas or adamant, the "unsubduable stone. The small, uncut, octahedral diamond crystals set in a very few Roman rings of the 4th century of our era, to be seen in the British Museum, represent all the positive evidence we possess that the diamond was known to the European world in ancient times. Still there is a certain amount of indirect evidence that the diamond-point was used by some of the later Graeco-Roman gem-engravers to a limited ex tent. The "point of a stone, more precious than gold° of the poet Manilius, who wrote in the 1st century A.D., has also been adduced as confirmatory testimony as to the importation of small Indian diamonds into the Roman world in early imperial times.
Authors and composers of Eastern tales long wrote of diamonds as being found in India only, and chiefly in the mines of Golconda —a mis nomer, as Golconda was the market, not the mine; and diamonds from many mines were sold there. But ever since the year 1728 these stones have been found in great abundance in Brazil, no less than 1,146 ounces having been taken from there to Europe in 1730. In 1829 a few diamonds were discovered in the Ural Mountains; and in 1867, in South Africa, John O'Reilly, a trader and hunter, reached the junc tion of two rivers, and stopped for the night at the house of a farmer named Van Niekerk. Children were playing with some pebbles they had found in the river. O'Reilly took one of these pebbles to Dr. Atherstone at Cape Town, who said that it was a diamond of 2254 carats. It was sold for $3,000. Niekerk remem bered that he had seen an immense stone in the hands of a Kaffir witch-doctor, who used it in his incantations. He found the man, gave him 500 sheep, horses and nearly all he possessed for the stone, and sold it the same day to an ex perienced diamond buyer for $56,000. This was the famous "Star" of South Africa. It weighed 85.77 metric carats in the rough, and was found to be a gem quite the rival of an Indian stone in purity and brillancy. After it had been cut it was bought by the Earl of Dudley, and is now known as the Dudley diamond. By 1869, parties in ox-wagons had worked their way over the plains to the Vaal River. Soon a tented city of 12,000 or more foreigners grew at Pniel and Klipdrift, on the opposite banks of the stream, where diamonds were found plentifully. Soon hundreds of cradles, like those used by the Aus tralian gold-diggers, were rocking on the edge of the stream, supplied with the precious gravel by a large force of diggers, sievers and carriers.