MANUFACTURE OF DIAMONDS.

Te Aroha News, Volume IV, Issue 206, 4 June 1887, Page 2

MANUFACTURE OF DIAMONDS.

Of late years the ingenuity of the Parisian chemists has resulted in compositions which imitate not only diamonds— the old pas,te •shams being nowadays quite out of date— but rubies, amethysts, and other stones, so perfectly that again and again experts Lave been docoived, and, it is all but certain, a great many other people who cannot claim that distinction. " DiamondVfaking '' has especially become an art. It is largely practised not only in London, which is 'the mart to which all the knaves bring their wares, but in Amsterdam, tho cento c of the diamond-cutting trade, and in New York, Avhore much easily-earned money goes into tlashy stones. Tho colour of a diamond being an important clement of its value, the most lucrative branch of this roguery is to make a yellow or "offcolour " stone look like one of the purest •water. There is, for instance, a red diamond which, though weighing only five grains is \ alued at L7OO. A blue stone, which was originally in the French crown, after being "" missing for some years, turned up in three pieces, one of which was purchased by Mr Hope, of Amsterdam, a second by the famous" Duke of Brunswick," while the third was many years later picked up in Vienna by Mr Streeter. What this gem was 01 iginally worth it is hard to say. But a green brilliant of seven grains i? now appraised at L5OO. Bluish-white stones command the greatest prices, as much as L2O the carat being given for some not of the very iirst quality » while white stones of the best description are readily purchasable for from LI 2 to L4O the carat. As for gems of the second quality they range from L8 to LI 2, while "off colour" stones will fetch only from L 5 to LlO the carat. But even the Americans who have of late been the principal purchasora of the bluish-white brilliants are beginning to grow timorous over recent revelations. The Old World scamp lias been "one too many,"' as they would say, for the'Xew World millionaire : for in hh 'laboratory he has managed to so manipulate an oil-colour stone, worth L 5 the carat, that it can pass muster for a bluish-white gem saleable at eight times the price. All that is required is to adroitly apply some blue paint indigo or blue ink Mill do -to the girdle or edge round the setting line of thu stone, and then after it is dry covering it with some hard transparent glaze, such as photocraphers use for enamelling their prints The stone is then so set that the "laked'' girdle is concealed by the gold, though the blue line, being refracted by the different facet*, the re-ult is a tint which it is hard to distinguish from tho genuino one, produced by the chemistiy ol Nature. In daylight, indeed, anyone might be deceived. But by gaslight detection is more easy, for instead of the faked stones appearing black a* night, as bluish-white ones always do, they preserve their colour intact. Again, a' diop of nitric acid will speedily destroy the indigo or inky hue, and even ordinary and water, while harmless to a real gem, will soon dissolve the enamel-covered paint. Moreover,asdiamonds have of hte years been cut, not with a rough girdle, but to ashaippoint at every angle, or v. hat is known a« a knife edge," the sophistication is only possible A\ith stones cut prior to the year 1870, when the Bessemer process came very generally into use. So f.ir there is no great occasion for alarm. But the holdeis of diamonds have other reasons for mortification, if not for dread. First-cla&s gems, if not too costly, are always saleable. " It is only when Kohinoor-* and Braganzas come on the market that purchasers do not appear, so that whi'e it is easy to figure up the value of these treasures, it might be found a great deal more difficult to realise anytning like the amount at which they are valued if they were exposed to auction. Small diamonds and off-coloured ones, however, fare less kindly. The immense discoveries of diamonds in South Africa within the last ten yoar.-i have seriously lowered the price of these stones ; and if the reputed field at Welsh ? Prospect in Barkly West should turn out well, there cannot fail, especially at a time when money is not very plentiful for superfluities, to be a further fall in the diamond maiket. B till, that is not all. If the chemical imitator ot stones has proved equal to " faking " poor stones into the likeness of first-class ones, he has been almost as successful in actually manufactuiing ones out of the barest materials. "Diamonds" are at piesent on sale which fla^h as brilliantly «v the real article— indeed, the only trouble i-. that they flash really too well— and will defy c^ cry test except that of the spectroscope. — " Morning Advertiser."