DIAMOND CUTTING
The Diamond, the hardest of all known bodies, can only be manipulated by means of powdered Diamond. This powder is prepared generally from bort, or faulty Diamonds, and from the refuse in cleaving and cutting, which, being put into a mortar of hardened steel, is pounded until it is fine enough for use.
The industry of Diamond cutting has been more or less in the hands of the Jews for the past 200 years. This may be attributed to the scientific and elaborate system they established of naming every facet on the Diamond and training the workman to detect at once the exact grain of that particular facet. They divide the work into four branches, assigned to the cutter, polisher, setter and cleaver, and these, all work into each other’s hands.
As an example we will take the cutter first. All the rough stones pass through his hands. His first care is to examine every stone minutely for flaws and imperfections, enabling him, to decide in which way the Diamond will give the best attainable results. This done he takes a cutter box having two iron pegs for levers, and affixing two Diamonds on the ends of two boxwood sticks, made specially for this purpose, he proceeds to cut the Diamond on the old fashioned principle of ” Diamond cut Diamond,” technically known as ” bruting.”
This is practically continued throughout the process, as there are no tools made of sufficient hardness to make any impression on the Diamond. Having decided which way to obtain the best result, the operator proceeds to cut the rough stone into a two-point, four-point, wass, drop briolette, rondelle, or tablestone. We will now follow the first mentioned of these, the two-point, in its passage through the other branches of the trade and the system carried out to the finish The stone having been cut to the satisfaction of the master, is handed to the setter who selects a suitable sized brass cup, fills it with a mixture of lead and tin, and melts it over the gas flame.
Having worked the solder to its proper shape, he places the Diamond in the centre, leaving only a very small part exposed. A mark is made on the solder before it becomes thoroughly set, and then the stone is passed on to the polisher. By the mark made on the solder the latter knows at once the precise run of the grain and the way in which it will polish to the best advantage on the mill.
The first operation is making the “table” of the Diamond. This done it is handed back to the setter that he may take it out of the solder and reset it for the operation of making the first corner, called the flat corner. The solder is again marked to indicate to the polisher the run of the grain of this particular corner, and so the process is continued until the Diamond is polished throughout.
Every facet has a name, and every name denotes the grain, and how to polish that particular facet. The polisher uses a mill or circular disc, composed of soft porous iron, so that as the Diamond is polished away in the form of dust it enters the pores of the iron, the result being that we have the Diamond cutting the Diamond.
Without the assistance of the Diamond dust the iron would not make the slightest impression on the Diamond. The next branch we have to deal with is the cleaving, an important part, but as only about 25 per cent, of the Diamonds found require cleaving the cleaver has not so much work to do as either the cutter or polisher. His work consists in taking a piece off a Diamond where it is too long, or making it into small stones where it is badly flawed, thus taking away all the impurities and defects, and leaving the sound parts to be cut and polished.
To cleave a Diamond he commences by fastening it to the end of a specially made stick with strong cement. A very sharp piece of Diamond, called a sharp, is similarly attached to another stick, and with it a V-shaped incision is made in the Diamond at the place where the part is to be removed.
Placing a blunt knife in the incision and giving it a sharp tap with an iron cleaver’s bar, the fragment immediately breaks off, if the incision is truly made and exactly on the grain. These fragments are cut and polished, and sold as Rose Diamonds. This is a distinct business from Diamond-cutting, but is carried out on exactly the same lines, the workmen requiring about the same length of time to learn either business, namely about six or seven years.
The great home for Diamond cutting is still Amsterdam, although, in order to diminish the price of cutting, Germany and Switzerland have also been tried—especially the latter, Switzerland being the great home for female labour ; but the result has not been satisfactory, as will be seen by the following statement.
A parcel of rough stones coming from the Cape was divided into three equal portions of 100 carats each, and sent to each of the above-named countries. The cost of labour in Germany was only 1s. 6d. per carat below that of Amsterdam, yet the stones lost so much by the cutting that their value was less by 10s.. per carat ; and in like manner those of Switzerland, were 20s. per carat lower in value.
Only highly skilled and very honest artizans are entrusted with the cutting of large Diamonds. When the Diamond passes from the cutter’s hands it is by no means perfect. The lustre and transparency for which it is so much valued are only fully developed in the hands of the polisher.
The polishing rocms of some of the great factories in Amsterdam, are well worthy of a visit. The grinding and polishing of the Diamond are effected on flat wheels propelled by steam-power, which make about 2000 revolutions in a minute. Before these silently revolving discs you will see men so intent upon their work that they have eyes for nothing else ; for, notwithstanding the perfection of the machinery, the skill of the workmen remains of primal importance.
It is with their fingers and thumbs that they adjust the points, edges and facets of the Diamond with extreme accuracy, keeping them constantly moist with Diamond dust and olive oil. The thumbs of the workmen being used continually, and with much force, not unfrequently become enlarged.
The lapidary, who is occupied with the cutting and polishing of other precious stones than the Diamonds, or who is engaged simply upon Semi-Precious Stones, arranges his work much in the same manner as the Diamond-cutter, but he uses other means for the cutting and polishing, according to the nature of the stone to be worked.
These special means’ will be noticed, where necessary, under the description of each particular stone.