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Information on polishing diamonds.
Diamond Polishing
By the next process the diamond is not only polished, but the remaining facets are formed. This is done by means of diamond powder, on a steel disk, called " skaif," which is made to revolve at a very high degree of velocity, by means of steamor horse-power. These wheels, or "skaifs," are prepared in the following man Diamond Polishing. 69 ner : The surface of the metal is rubbed with an ordi nary whetstone, in such a direction as to form tangents of a circle, whose diameter is about a third of that of the " skaif." By this means the whole surface becomes covered with deep indentations, or scratches. Then a fine hone or Turkey stone is rubbed over again in the direction of the diameter, until the former marks are nearly obliterated ; and by the crossing of the scratches a kind of soft grain is formed, which makes the metal fit to receive and retain the diamond powder, which is then spread on the skaif with olive oil, and the flat surface of a finished diamond held against it whilst in motion j by these means the powder is forced into the wheel.
The diamond to be polished is then inserted into a stick having a handle made of brass, with a hollow top filled with solder, into which the diamond is pressed whilst melting, and then allowed to cool ; the diamond is thus fixed in its proper position. Of course, when one facet of the stone is polished, the solder must be melted, and the stone removed and replaced in an other position.
This process completes at the same time the required shape of the diamond, and gives the necessary polish when the stone is ready for use. The work, as may be supposed, demands the greatest nicety : the least inat tention or irregularity may spoil the stone ; and when the minuteness of the facets required on a stone, some of which are so small that a thousand only weigh one Carat, Is considered, it will be readily understood that this process demands workmen skilled in a high degree.
The stones which, from their formation, are not adapted for the double cutting, as well as the splinters from other diamonds, are made into single cut, a description of which is given hereafter. The rest are cut into brilliants or roses, of which the finest are sorted out for this country, die second quality sent to the Paris market, and the inferior descriptions to South America, Poland, Turkey, etc. The best and most experienced judges are however unable to determine with certainty what any stone will be when polished, as, in the process of cutting, flaws and imperfections are often laid bare, which go much deeper than the appearance of the rough diamond would predict ; and, on the other hand, the colour, ap parent in the rough stone, is sometimes found to arise from the presence of flaws or specks, which are re moved in cutting, thus leaving the stone white.
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Diamonds 
