ARTIFICIAL GEMS

Dominion, Volume 21, Issue 120, 18 February 1928, Page 19

ARTIFICIAL GEMS

A natural sapphire in these days is something of a rarity. In 1910 these stones were worth £lO a carat, but in that year a process for their artificial manufacture was discovered which turned out stones at a cost of 10s. a carat. These artificial gems cannot be distinguished by any knewn test from the natural ones, and the . result has been the dying out of sapphire mining (says an exchange). About 15,000 carats of sapphires have been made daily for years, their chief use being in watchmaking. Sapphires are the most successful scientific effort to date in tlie manufacture of gems. Diamonds have always been foremost in public interest, because of their great value and' romantic atmosphere, and in this case artificial stones of small size have been made by several chemists. The chief method is by dissolving carbon in molten iron and plunging the mass suddenly in freezing water. The tremendous pressure resulting stimulates the natural volcanic explosions which formed natural diamonds. Unfortunately, these stones cost as much to produce as the real stones. Artificial rubies were first made in 1902, and up to about five carats size are the equal of the natural stones. As th.ev go larger, however, they lose their fineness of appearance.