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DIAMOND CUTTING
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See also:DIAMOND CUTTING .—On See also:account of its extreme hardness, the treatment of the diamond in preparation for use in See also:jewelry constitutes a See also:separate and See also:special See also:branch of the See also:lapidary's See also:art. Any valuable See also:gem must first be trimmed, cleaved or sawed into suitable shape and See also:size, then cut into the desired See also:form, and finally polished upon the faces which have been cut. The stages in diamond working are, therefore, (1) cleavage or See also:division; (2) cutting; (3) polishing; but in point of fact there are four processes, as the setting of the See also: In this process, each of the diamonds is fixed in See also:cement on the end of a stick or handle, so that they can be held firmly while one is applied to the other. When the stone is large and very valuable, the cleaving is a most See also:critical process. See also:Wollaston in 1790 made many favourable transactions by buying very poor-looking flawed stones and cleaving off the See also:good parts. In the case of the immense Excelsior diamond of 971 carats, which was divided at See also:Amsterdam in 1904, and made into ten splendid stones, the most elaborate study extending over two months was given to the See also:work before-See also:hand, and many See also:models were made of the very irregular stone and divided in different ways to determine those most advantageous. This process was in 1908 applied to the most remark-able piece of work of the See also:kind ever undertaken—the cutting of the gigantic See also:Cullinan diamond of 30254 See also:English carats. The stone was taken to Amsterdam to be treated by the old-fashioned hand method, with innumerable precautions of every kind at every step, and the cutting was successfully accomplished after nine months' work (see The Times, Nov. ro, 1908). The two See also:principal stones obtained (see DIAMOND), one a pendeloque or drop brilliant, and the other a square brilliant, were given 72 and 64 facets respectively (exclusive of the table and cullet) instead of the normal 56. This process of cleavage is the old-established one, still used to a large extent, especially at Amsterdam. But a different method has recently been introduced, that of sawing,' which is now generally employed in See also:Antwerp. The stone is placed in a small See also:metal receptacle which is filled with melted See also:aluminium; thus embedded securely, with only the part to be cut exposed, it is pressed firmly against the edge of a metallic disk or thin See also:wheel, 4 or 5 in. in See also:diameter, made of See also:copper, iron or phosphor See also:bronze, which is charged with diamond dust and oil, and made to revolve with great velocity. This See also:machine was announced as an See also:American invention, but the form now principally employed at Antwerp was invented by a Belgian diamond cutter in the See also:United States, and is similar to slitting wheels used by gem The Universal See also:Magazine of Knowledge and See also:Pleasure for 1749 states that diamond dust, " well See also:round and diluted with See also:water and See also:vinegar, is used in the sawing of diamonds, which is done with an iron or See also:brass See also:wire, as See also:fine as a See also:hair."—Ed. the old hand method is already replaced in part by an improved See also:device whereby the diamond is held by adjustable claws, on a See also:base that can be rotated, so as to apply it in any desired position. By this means the See also:time and trouble of repeated re-setting in the clop are saved, as well as the liability to injury from the See also:heating and cooling; the services of special " setters " are also made needless.
The rapid development of See also:mechanical devices for the several stages of diamond cutting has already greatly influenced the art. A very interesting comparison was brought out in the thirteenth See also:report of the American See also:Commissioner of Labour, as to the aspects and relations of hand-work and machinery in this branch of See also:industry. It appeared from the data gathered that the See also:advantage See also:lay with machinery as to time and with hand-work as to cost, in the ratios respectively of r to 3.38 and 1.76 to 1. In other words, about See also:half the gain in time is lost by increased expense in the use of machine methods. A great many devices and applications have been See also:developed within the last few years, owing to the immense increase in the See also:production of diamonds from the See also:South See also:African mines, and their consequent widespread use.
See also:History of Diamond Cutting.—The See also:East See also:Indian diamonds, many of which are doubtless very See also:ancient, were polished in the usual See also:Oriental See also:fashion by merely rounding off the angles. Among See also: See also:Peruzzi was the artist who worked out the theory of the well-proportioned brilliant of 58 facets. Some very fine work was done early in See also:London also, but most of the workmen were See also:Jews, who, being objectionable in See also:England, finally betook themselves to Amsterdam and Antwerp. Efforts have been lately made to re-establish the art in London, where, as the great diamond mart of the See also:world, it should peculiarly belong.
The same unwise policy was even more marked in See also:Portugal. That nation had its colonial possessions in See also:India, following the voyages and discoveries of Da Gama, and thus became the chief importer of diamonds into Europe. Early in the 18th century, also, the diamond-mines were discovered in See also:Brazil, which was then likewise a Portuguese See also:possession; thus the whole diamond product of the world came to Portugal, and there was naturally developed in See also:Lisbon an active industry of cutting and polishing diamonds. But in time the Jews were forced away, and went to See also: But the chief importance of his work lay in its See also:superior quality. So See also:long had it been a See also:monopoly of the Dutch and Belgians that it was declining into a See also:mere mechanical See also:trade. Morse studied the diamond scientifically and taught his pupils how important mathematical exactitude in cutting was to the beauty and value of the gem. He thus attained a perfection rarely seen before, and gave a great stimulus to the art. Shops were opened in London as well, in See also:con-sequence of Morse's success; and many valuable diamonds were recut in the United States after his work became known. This fact in turn reacted upon the cutter abroad, especially in See also:France and See also:Switzerland; and thus the See also:general See also:standard of the art was greatly advanced. Diamond cutting in the United States is now a well-established industry. From 1882 to 1885 a number of American jewelers under-took such work, but for various reasons it was not found practicable then. Ten years later, however, there were fifteen firms engaged in diamond cutting, giving employment to nearly 150 men in the various processes involved. In the See also:year 1894 a number of See also:European diamond workers came over; some See also:foreign See also:capital became engaged; and a rapid development of diamond cutting took place. This movement was caused by the See also:low See also:tariff on uncut diamonds as compared with that on cut stones. It went so far as to be See also:felt seriously abroad; but in a year or two it declined, owing partly to strikes and partly to legal questions as to the application of some of the tariff provisions. At the See also:close of 1895, however, there were still some fourteen establishments in and near New York, employing about 500 men. Since thenthe industry has gradually developed. Many of the European diamond workers who came over to See also:America remained and carried on their art; and the movement then begun has become permanent. New York is now recognized as one of the chief diamond-cutting centres; there are some Soo cutters, and the quality of work done is fully equal, if not superior, to any in the Old World. So well is this fact established that American-cut diamonds are exported and sold in Europe to a considerable and an increasing extent. In the Brazilian diamond region of See also:Minas Geraes an industry of cutting has grown up since 1875. Small See also:mills are run by water See also:power, and the machinery, as well as the methods, are from Holland. This Brazilian diamond work is done both well and cheaply, and supplies the See also:local See also:market. The leading position in diamond working still belongs to Amster-See also:dam, where the number of persons engaged in the industry has trebled since about 1875, in consequence of the enormous increase in the world's See also:supply of diamonds. The number now amounts to 15,000, about one-third of whom are actual cleavers, cutters, polishers, &c. The number of cutting establishments in Amsterdam is about seventy, containing some 7000 mills. Antwerp comes next with about half as many mills and a See also:total of some 4500 persons engaged in all departments, including about seventy women. These are distributed among See also:thirty-five or See also:forty establishments. A See also:majority of the workers are Belgians, but there are many Dutch, Poles and Austro-Hungarians, principally Jews. Among these numerous employees there is much opportunity for dishonesty, and but little surveillance, actual or possible; yet losses from this cause are almost unknown. The wages paid are good, averaging from £2, 9s. 6d. to £2, 17s. 6d. a See also:week. Sorters receive from 28s. to £2; cutters from £2, 9s. 6d to £3, 6s., and cleavers from £3, 14s. upwards. With the recent introduction of See also:electricity in diamond cutting there has been a revolution in that industry. Whereas formerly wheels were made to revolve by See also:steam, they are now placed in See also:direct connexion with electric See also:motors, although there is not a motor to each machine. The saws for slitting the diamond can thus be made to revolve much more rapidly, and there is a cleanliness and a See also:speed about the work never before attained. (G. F. Additional information and CommentsThere are no comments yet for this article.
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