How To Cut A Diamond

The uncut diamond looks like a piece of quartz. Is is of a dull white color and is full of rough seams. In this condition it is set into a matrix of wax, which is fastened to the end of a stick. The wax becomes very hard when cooled. In another matrix a cheap diamond is set, and a workman grinds the two stones together, until the one to be cut assumed the general form of a brilliant. The dust and chips which come off are carefully collected and used afterwards in polishing work. The rough stone is then firmly fixed in a matrix of metal, composed a zinc and lead, and set into a cup shaped instrument of iron. The workman is then ready to begin cutting. In this process an iron disc turning at the rate of 2,000 revolutions a minute is used. Upon the disc is sprinkled a supply of diamond dust, which sinks into the minute pores of the iron and produces the sharpest grindstone that can be made.

The workman, with a magnifying glass close to his eye, grinds first the table, or top part, of the brilliant. This completed, the metal matrix is melted from the stone, which is put in, face downward, so that the exact opposite of the stone will be ground. After this, one by one, the facets, or bezils, are cut, the first two opposite and parallel, and the second two at right angles to the first two. If the diamond is large, the corners remaining between the four opposite cuts are also beveled. Then the stone is turned over in its matrix, and the facets between the girdle and the point known as the collet are cut in the same way. Rubies and sapphires are cut in the same general process. Moss agate, topaz, agate, amethysts and other semi-precious stones are first sawed into proper size with a soft tin wheel. When the agate, for instance, has been sawed to the proper shape, it is smoothed down on an ordinary grindstone and then is taken by hand by the polisher, who applies it to a fine grindstone, and, after being ground for about an hour, it is ready for the market.