Cutting and Polishing Diamonds

Diamond cutting and polishing originated in India, and the art was afterwards introduced in Italy and in Paris. It had its beginning in Antwerp, about 1480, and also about the same time in Amsterdam. Amsterdam has become famous for its diamond cutting, and for a long time had by far the largest number of cutting and polishing establishments in the world.

Antwerp for some years has had some of the largest establishments, and during the last six years has gained rapidly on Amsterdam, and at the present time has a considerably larger business in the cutting and polishing of diamonds than Amsterdam.

Diamond cutting has been carried on in America for many years and the cutting of diamonds for the world has been revolutionized through the improvements in cutting made something like one hundred and thirty five years ago by Henry D. Morse, of Boston.

Prior to these innovations diamonds were cut in a nearly square shape, with the corners somewhat rounded off, the object being to secure as much brilliancy and also to save as much weight as possible. Diamonds are now cut, as every one knows, practically round. The style of cutting may be described as follows:

The table on the top of the stone is surrounded by thirty two small facets reaching from the table to the girdle, or edge of the stone. The back of the stone has a tiny facet at the top of the pyramid, formed by cutting, called the culet, surrounded by twenty four facets reaching from the culet to the girdle.

Formerly and even now in most of the ordinary cutting comparatively little attention is paid to the girdle; but the better the quality of the cutting the more attention is paid to the desirability of having the girdle as thin as possible, and yet not so thin as to chip easily. This object is attained in the patented polished girdle form of cutting, which has an extra curved facet around the girdle. This cutting process is protected by patents in the United States and in foreign countries, and in New England is sold direct only to the Smith Patterson Company.

In describing this cutting we will quote a letter of March 14, 1913, from the holders of the patent, Messrs. Schenck & Van Haelen.

Before its final realization the quest for a Standard of absolute perfection in the cutting of a diamond has been one which ran through centuries of constant endeavor.

Incidentally it has brought into existence that interesting branch of the trade called 'fancy cutting.' It has been responsible for many sad disappointments and disillusions. Witness in 1885 the short lived 'Brilliant Phare,' later revived under the name of 'Twentieth Century,' etc.

By a stroke of genius the fundamental lines of division governing the now classical cutting called 'Brilliant' were laid down some four hundred years ago by Vincent Peruzzi, in Venice. The cutting at that period was done in crude and primitive fashion, but it paved the way towards the high achievement.

The latter day Renaissance in the art of diamond cutting, credit for which is entirely due to the keen appreciation shown by the discerning lovers of jewels in the United States of America, has through gradual stages of advancement developed the possibilities inherent in the 'Brilliant,' and has culminated in the production of an ideal stone, the cutting of which is covered by patents in the United States and in the principal foreign countries.

The superiority of this diamond resides in its dominant feature: The polished curved facet encircling edge of the stone, forming a continuous narrow girdle, establishing in harmony with every detail of its cutting a connecting link joining all its facets into one final attainment of perfection.

This patented Polished Girdle, with its resultant increase in luster and brilliancy, produces a maximum diffusion of light with corresponding depth of attraction.

The smooth finish of the edge protects the patented Polished Girdle diamond against injury by 'chipping,' an advantage that both setter and wearer will appreciate.

The Polished Girdle of this diamond furthermore provides efficient means of identification; the cylindrically shaped facette acting as an indelible hall mark embodied in the stone.

It is indisputably the first and only perfectly finished brilliant, a Standard for all time.

Isolated attempts have been made more recently by some of the followers of Peruzzi to give increased luster to the brilliant by adding to the unfinished stone flat polished surfaces spaced at more or less irregular intervals, disturbing the line of circumference without attaining the desired result. It is superfluous to point out that such makeshifts destroy their own ends.

To the expert jeweler and diamond dealer, no further explanation is necessary to make him realize the advantages and superiority of the patented Polished Girdle diamond.

The person more likely to be in need of guidance and information is the purchaser not thoroughly conversant with the art, and who, wishing to ascertain points of recognition, relies upon his confidence in the knowledge of experienced "jewelers."

A properly cut diamond should have fifty eight facets if regularly cut, and fifty nine if cut as a patented polished girdle. One third of its size should be above the girdle and two thirds below, and the table should be two fifths the diameter of the stone. These are the correct proportions to secure the greatest brilliancy. A stone cut too deep (too thick that is) lacks brilliancy, and one too shallow becomes flat in its effect and in the trade is termed a Fish eye. In the cutting of the finest diamonds much consideration is now given to the girdle, while on the other hand many ordinary stones are cut with thick, rough girdles, which results in more weight being left in the stone and less expense to manufacture per carat, consequently a lower price to the customer by the carat. But it must be remembered that a poorly cut stone will not look as large as a stone of slightly less weight, if the latter is well cut.

Fine diamonds, especially those of considerable size, are cut into drop shapes, navettes or marquise shape, square cut or emerald cut, square cut with steps, and oval, the last being cut like a round brilliant, but of oval shape. Small pieces from the processes of cleaving and sawing diamonds are generally rose cut, with flat back. It is due probably to this fact that the rose cut stones come from the fragments that they are commonly termed chips. In the old days of cutting many of the famous stones were rose cut, having when properly cut twenty four facets. A correctly proportioned rose should be one half its diameters in thickness. Smaller and poorer roses have twelve facets.

Before being cut the rough diamonds are first examined by an expert, who decides how each stone shall be treated, and who then marks on the stone with ink what part of the stone shall be removed by cleaving or sawing, in order to get it in proper shape for further work.

In the process of cutting, rough diamonds are generally cleaved or sawed to render them suitable in size for cutting. If it be cleaved, the rough diamond is fastened with cement to the end of a wooden holder and a tiny groove is scratched with another diamond on the stone at the point where it is to be cleaved. The stone is then held by the clamp in correct position, and then a heavy steel blade is placed on the diamond, and this blade is struck a smart tap on the back and the stone divides along the line previously determined. The operation seems very simple, but is on that requires excellent knowledge of the stones as well as experience.

Sawing has been used some and enables the cutter to divide the stone along any plane, independent of its structure, while a diamond can be cleaved only along its natural cleavage lines. The diamond saw is about three and one half inches in diameter, and consists of a very thin piece of a special alloy, the edge of which is treated with diamond dust. The work is done very slowly, several hours being required to cut one diamond, so that one workman operates a large number of saws at the same time.

After being cleaved or sawed the stone is again examined by an expert, and a plan for further work on that particular stone is determined on. The most important point in this is the location of the table, which when decided upon is marked with an ink circle.

The next step in the process is that called cutting. This work was done entirely by hand, and was called bruiting, until about twenty five years ago, when machine cutting came into use. In machine cutting a rough diamond is fixed by cement in a steel holder held in a lathe and is cut by another diamond, which is also fixed into a steel holder attached to a handle some eighteen inches long, this latter diamond being held against the one in the revolving lathe and the cutting done much after the manner of wood turning. The stone is cut very rapidly as compared with the old method of bruiting, the method which had been used from the time of the first cutting of diamonds until the advent of machine cutting. Machine cutting, however, can be sued only for round and oval diamonds, and for the round ends of pear or drop shape diamonds. Marquise shape, square or emerald cut, and other fancy shapes must still be cut by hand.

Diamonds were polished on a polishing wheel covered with diamond dust and oil. The wheel is about eleven inches in diameter and made from a special casting of a secret alloy that was only known by two men, one in Amsterdam and one in Antwerp. The wheel was set to revolve horizontally at the rate of about twenty two hundred revolutions per minute. The time needed to polish a diamond, say of about one carat, after it has been shaped up ready for the carat, after it has been shaped up ready for the wheel, is, depending on its hardness, from two to four days.

The diamonds to be polished were formerly always imbedded in a composition of lead and tin while the metal was in an almost fluid state. In this case the workman sets the stone in position at the proper angle with a pair of pliers and smoothes the still almost molten metal with his bare fingers. It seems to the observer that it is a miracle that the man does not burn his fingers, until it is noticed that they have been calloused by the hot metal to a condition almost like that of leather.

After each facet has been polished the diamond must be removed and reset before a new facet can be begun. The patent dop, invented about one hundred and ten years ago, which allows the stone to be set at the desired angle and held by clamps, is about the only improvement in the process of polishing for many years. This improvement cannot, however, be used in the polishing of melees, marquise, square, and other fancy shaped diamonds in which the old fashioned dop of soft metal must still be used.

By a perfect diamond is meant in the trade a diamond without flaw or spot which can be discovered by using an ordinary magnifying glass by a person whose eyes are ordinarily strong. Scientifically the perfect diamond does not exist, as all diamonds must show imperfections if a glass powerful enough be used. Imperfections, termed flaws or feathers, are due to carbon spots or minute cracks. Commercially, perfect diamonds or slightly imperfect and even imperfect diamonds are equally staple and salable. The actual value of the stone is on course determined by its color, brilliancy, freedom from discernible imperfections or conspicuousness of flaws if they exist, and size.

The question often comes up whether diamonds used in the United States can best be bought by diamond merchants from cutters in America or from the cutters in Europe. To those who have made a study of the question there can be no doubt that in sizes from one half a carat and larger, the American cutters, if properly equipped, are able to produce and deliver finished diamonds to the trade in the United States cheaper than the same goods could be bought and landed, duty paid, from European cutters.

The progress made here in economic handling of rough merchandise has almost reached the point where, should the duty be removed from the cut as well as it is removed from the rough diamond, I firmly believe the industry would, in the United States, through better workmanship, triumph and grow over all others, even on equal footing.

Several causes lie at the bottom of this: one hundred and fifteen years ago the cost of manufacture represented, say, about fifteen percent of the price of the finished article; twenty years later, with the doubled value of the rough material it represents only about ten percent.

Furthermore, if many years ago, at a time when protection to industries was thought necessary, an average of less than ten dollars per carat was found more than sufficient, what is the obvious conclusion to be drawn today, when this same duty means on the same goods much more per carat?

On the other hand, trade unionism has increased in Europe even more and with greater reason than it has in the United States; and the demands have become more urgent in full ratio to the abuse of labor that has been practiced in the old countries. The result was that the few good artisans who had not emigrated to more hospitable shores, together with the mass of poor workers remaining over there, have gradually found better terms granted them, with shorter hours of work, than had ever been the case heretofore. In consequence there is today a constant narrowing down of the difference between the two scales of wages, and it will not be long before almost equal compensation will prevail in Antwerp and Amsterdam, as well as in America, for the best workmanship in diamond cutting.

Diamonds have, since 1898, steadily advanced in price and are still advancing. This is due, we believe, first to the difficulty in actually mining the world's supply of diamonds, and second to the fact that through the methods of business of the two great companies, the DeBeers Consolidated Mines, Ltd., and the London Syndicate, which combined form virtually a monopoly, they were able to control the entire diamond market and to regulate prices. For many years these two companies had made the diamond market secure. The extent of the rise in prices has, meanwhile, been very great, and it is safe to say that diamonds are today worth much more in value of the same goods in 1898.

Perhaps the greatest advance in this general rise in value has been on fine crystal or Wesselton two grainers, or half carat diamonds, which have advanced many times their value since 1898. Silver Capes and the best of the cheaper goods have advanced rather more than blue white and Wesseltons, except in the half carat sizes of the latter.

On the other hand, trade unionism has increased in Europe even more and with greater reason than it has in the United States; and the demands have become more urgent in full ratio to the abuse of labor that has been practiced in the old countries. The result was that the few good artisans who had not emigrated to more hospitable shores, together with the mass of poor workers remaining over there, have gradually found better terms granted them, with shorter hours of work, than had ever been the case heretofore. In consequence there is today a constant narrowing down of the difference between the two scales of wages, and it will not be long before almost equal compensation will prevail in Antwerp and Amsterdam, as well as in America, for the best workmanship in diamond cutting.

Diamonds have, since 1898, steadily advanced in price and are still advancing. This is due, we believe, first to the difficulty in actually mining the world's supply of diamonds, and second to the fact that through the methods of business of the two great companies, the DeBeers Consolidated Mines, Ltd., and the London Syndicate, which combined form virtually a monopoly, they were able to control the entire diamond market and to regulate prices. For many years these two companies had made the diamond market secure. The extent of the rise in prices has, meanwhile, been very great, and it is safe to say that diamonds are today worth much more in value of the same goods in 1898.

Perhaps the greatest advance in this general rise in value has been on fine crystal or Wesselton two grainers, or half carat diamonds, which have advanced many times their value since 1898. Silver Capes and the best of the cheaper goods have advanced rather more than blue white and Wesseltons, except in the half carat sizes of the latter.