JEWELS BY ELECTRICITY

Waipa Post, Volume 42, Issue 3305, 4 June 1931, Page 3

JEWELS BY ELECTRICITY

TEN-TON RUBIES NOW. The' wealthy rajahs of India are very'partial to the ruby. Over there it is a very poor ruler indeed who has not at least one of those bloodcoloured stories among his jewels, and when some great event of the Orient brings these little-known magnates

together they, do not hesitate to dis-

play their treasured posessions. It &11 unusual to see a turban a ruby in it about the size of a half-crown piece and weighing upwards of an ounce and a-half or possibly two ounces. The ruby is still the favoured jewel of the east, but has lost some of its' glamour in the west owing to the

ability of the electro-chemist to duplicate nature in the art of making rubies. These man-made rubies are sometimes styled artificial rubies, but they are not artificial. They are really synthetic rubies and are identical with the natural product in lustre, weight and colour. Modern science has also been enabled to duplicate the samphire, the emerald, the topaz, and the zircon. All these can be made of considerable size and weight and will measure up to every test that is applied to the natural product. • Modern science can also make tiny diamonds in the electric furnace, but so far the secret of getting large diamonds has not been revealed. The largest man-made diamond yet constructed is but one-fiftieth of an inch in diameter. These synthetic diamonds although mere miscroscopic curiosities, have hardness and the crystalline characteristics of the mined product. The synthetic gem business has many queer twists to it, and whereas the diamond has so far baffled man to reproduce it in any commercial size, man has made rubies that surpass the gems from Burma. The largest rubies ever found on the Burmese slopes of the Himalayan foothills weigh two and a-half and three ounces each. Electro-chemists are makirig rubies every day They are not weighted or considered in ounces or pounds, for these gigantic specimens from the electric furnace infernos weigh no less* than ten tons each. No, they are not made to fabricate a necklace for an elephant! •In the manufacture of synthetic rubies for jewellery it is possible to duplicate the colour and all the other characteristics of the natural rubies. This includes the quality of hardness, for the ruby is almost as hard as the diamond. In the manufacture of tenton rubies the colour is of no importance, and the tiny trace of- chromium salt, that is needed to give colour is omitted. What a “ ruby ” fac-

tory is after is the hardness, and they ' crack their gigantic rubies down into grinding wheels and other abrasive tools. The diamond is pure crystallised carbon, but the ruby, sapphire, and a host of other precious stones, have as their chemical base the metal aluminium. It is the oxides of this metal that are treated in the electric furnace to produce the synthetic ruby. Tn the manufacture of synthetic rubies for jewellery the greatest care is taken in feeding the aluminium salt into the electric furnace. In the manufacture of rubies for grinding wheels the material is shovelled m with a spade. . Carbons, upwards of a foot m diameter, dip into the body of the furnace, and, under a current of several amperes, a great arc is created. The arc is surrounded by the furnace wall, A w hich is of steel and water-cooled. Men with’ their eye protected by heavy goggles shovel in the mixture from a nearby bin. The aluminium ore mixture is thrown by the spade ■ right into the arc. It melts and starts to form the gigantic ruby that is' to result. Hours and hours of shovelling fill the furnace with the molten mass, and by that time the gigantic carbons have all but burned current is turned off and the mass rested until the outer crust has solidified. Then a massive crane lifts the steel shell out on to the sand floor, and the ten-ton ruby is set aside for a week or so until it cools right through. It is a spectacular sight to see the row of furnaces burning but to direct the gaze away toward m sand floor and to behold rows an rows of monster rubies cooling is to realise something of what electric power has meant to t e we - tieth century. _____ ’