The daily morning journal and courier., 1906-04-12
RUBIESAND DIAMONDS.
PRODUCTS THAT GRIVAL BEST
 NATURAL STONES.

- ~ DN v
 Results of Experiments by Chemists
 Black Diamonds Made by NJ. MOissan
 Principle Upon Which He Worked
 Attempts to Manufacture Rubies.
 It. has long been a favorite object with chemists and mineralogists to re- produce mineral substances, and more particularly gems, by artificial means. Such artificial gems are of course quite distinct from glass or paste limitations. What is aimed at is of course the pro- duction of the very identical sub stance, with all it's chemical and crys- tallographic peculiarities. It will be interesting to survey recent progress ill this direction with the two valuable stones, writes the Hon. R. J. Strut in the London Tribune.
 Diamond and ruby are both crystal line substances; that Is to say, their | ultimate particles, or molecules, are arranged in definite and orderly manner. The structure of a crystal may be compared to that of a battalion | of well drilled soldiers. the structure iof a n-crystalline substance, such as glass, to that of an Irregular mob. This crystalline structure is on far toe minute a scale to be directly perceived, even with a powerful microscope; but there are many Indirect indications of it's presence. For instance some crys- tals, notably the diamond, split quite easily and regularly in one particular set direction. This reminds one of the way in which a regiment on parade may be exactly divided at any rate, in imagination, by lines drawn in special directions.
 | In order to produce a crystalline structure it is generally necessary to obtain the substance to be operated up on in a liquid condition either melting 1t by heat or dissolving it in some suitable liquid. Then, on evaporating the solution aud allowing the liquid to cool crystals to separate out. The size and perfection of these crystals depends to a great extent on how slow ly they have been deposited. By slow evaporation of a solution of alum enor- nous alum crystals of perfect regu- laritE can easily be obtained. Most mineral substances are, Glowever, much more difficult to deal with.
 Tn the case of diamond the problem is to convert carbon of the non crystalline form Qampblack, for instanee) into the crystalline form (diamond) No liquic is known which will dissolve carbon al such at the ordinary temperature, ant deposit it on evaporation nor does | appear particularly probable at presen
 that chemistry will ever be able to fur
 nish such a solvent. There Is, however a liquid which will dissolve carboon a
 a white i1eat-namey, molten iron. Th'
 carbon separates out on qualification
 but, unfortunately, not In the form o
 diamond. Common cast iron contain
 carbon which Is separated out on cool ing, but 1t. is carbon in the form 0
 graphite or black lead.
 M. Moissan, who was the first to sue
 ceed in producing diamond reiecte, that the diamond found at Kimberle. evidently come from great depth il
 the earth and that they must therefor be formed under great pressure. H determined to attempt the soldificatiol of iron saturated with carbon at yer nigh temperature under these condi tions. This would not have been practicable but for the fortunate cir cumstance that iron is one of the fel
 substances which expand on solidifica ton. His plan was suddenly to chi the outside of the iron, so as to forr solid and unylelding shell, while tn intesior remained liquid. When, ther the interior did eventually solidify, ,, had no room to expand in and con sequently was exposed to enormou pressure.
 It must have originally required n little courage to seize with the tong a crucible coitainiing molten iron at 5 dazzling white heat and to plunge I into cold water. A serious explosio l might well have been feared, It is nc
 found, however, that there Is any ter
 dency to this in practice. When tn
 cooling of iron takes place under thes 7 conditions carbon does crystalline ou
 in the form of diamond On dissolvin ' the iron with acid, few minute blac $ diamonds can be extracted from th @ residue.
 I Black diamonds, though not of gres I value like white ones, are, none tf, less, of great industrial importance g / an abrasive agent Thus diamond du'
 is essential for cutting the harder gen i. generally, and larger black diamond : are most necessary for drilling hole . through hard rock, in mineral pro-