All About Cutting Diamonds and Other Gems

Precious stones in the rough are seldom things of beauty. The most valuable gem stones might be dismissed with contemptuous glance by an inexperienced finder, as no doubt has often been the case. Ancient gems that have been benefited only to the extent of the crude handiwork of the artisans of their period, reveal but little of the imprisoned chromatic beauty and flaming splendour that would make them magnificent under the scientific and artistic treatment of a modern diamond-cutter or lapidary. Thus the work of the highly skilled artisans, who cut diamonds, with their cooperators, who set the diamond in a tool with which the cutter applies the rough stone to the grinding wheel, and the toil of the lapidary, who cuts, forms, and polishes semi-precious stones, are of the greatest importance in making possible the beauty and value of gems. Here it may be said that the craft of the diamond cutter and the trade of the lapidary are absolutely separate and distinct in the methods that each employs in cutting and polishing gem minerals. The diamond cutter cuts diamonds only. The lapidary cuts and polishes all other precious and semi-precious stones. Both diamond cutter and lapidary prepare the way for the craft of the jeweller, to whose judgment and art in design and manufacture the cut gem owes its environment, which will go far to increase or mar its beauty. For the jewellers' art is as important to the gem as the scenic artist's and stage manager's is to the actor's dramatic art; and without intelligent co-operation, the jeweller might detract from the appearance of a gem that the capable diamond cutter or lapidary has done so much to enhance.

Thus the cutting of gem stones is necessary for the full development of the inherent properties upon which their beauty is dependent. A gem, as extracted from the earth, may be opaque, irregular in form, and contain superficial flaws and imperfections; but when relieved of its incrustations and reduced to a size that would permit of the elimination of its imperfect portions, it becomes transparent and its imprisoned fires are released in brilliant flashes. Occasionally a gem does appear which, without artifice, may plainly show its qualifications for high rank in the court of gems; but, in the main, the development of its beauty to a high degree necessitates cutting and polishing. The highly specialised work of the diamond cutter or lapidary involves compliance with geometrical principles and rules; adaptation to the place occupied by the gem stone under treatment; a knowledge of the clearly defined science of crystallography, especially with regard to the planes of cleavage; careful consideration of the stone's degree of hardness, brittleness, and a thorough acquaintance with the established forms of cutting and the results achieved through them with different kinds of gem minerals and their chromatic varieties.

The art of gem-cutting has progressed gradually from the crudest beginning. Man's first attempts to artificially improve the appearance of gem stones extended only to polishing the natural surfaces; later, the worker essayed to round the rough corners, and in the course of the evolution of this art, efforts were made to reduce the stone to a symmetrical shape. Gem-cutting by Oriental workmen, in the island of Ceylon, Burma, and India, has, even now, advanced but little beyond its crude beginnings. The Asiatic artisan uses a polishing disc on the left end of a horizontal wooden axle, which revolves in sockets on two upright pegs driven into the earth or set in the timbers or boards which floor his dwelling or shop. The motor for this machine is a long stick to which a cord is tied, as to a bow, at each end, one turn having been taken around the axle; the motive power is supplied by the right hand and arm of the operator, who moves the stick back and forth; there is usually no holding tool; the stone is held in the fingers of the left hand and thus pressed against the surface of the polishing wheel. The abrasive powders of corundum or some mineral nearly as hard, mixed with water to a paste of suitable consistency, are at hand, contained in the halves of cocoanut shells. The earliest record of the artificial improvement of gems by the ancient Greek and Roman artisans proves them to have had higher ideals and more invention then Orientals, especially in the matter of imparting to stones symmetrical forms; the greatest advance they made, however, in the treatment of gem minerals, was in their art in cutting cameos and intaglios, their engraving of gems having early reached a surprisingly high state of perfection.