Historical Attempts of Diamond Reproduction

Two hypotheses arrest consideration in examining the probable origin of the diamond; the first conceives of carbon as having been melted by a strong heat, and the diamond having crystallized in an excess of liquid; the second supposes a body capable of dissolving carbon, and allowing it to crystallize by evaporation.

Another theory was advanced by Sir David Brewster concerning the origin of the diamond. He supposed that this beautiful gem is of organic origin, and he was led to this opinion by examining the diamond microscopically, when he discovered certain striations and dispositions that resembled the fibres of organic substances, and particularly of certain species of wood.

These are but suppositions, however, and we really know nothing for certain regarding the origin of the diamond. The most we can say is that it is very improbable the diamond was produced under the action of a high temperature.

The knowledge of the chemical composition of the diamond is so recent that all the experiments made with the least chance of success to reproduce it have occurred within the last half century.

In 1828 two interesting experiments were made nearly at the same time by Cagniard de Latour and Gannal; De Latour presented his results to the Academy of Sciences, Oct. 10, 1828; and those of Gannal were presented the 23d of November the same year.

Cagniard de Latour sent to the Academy of Sciences ten tubes containing a number of lightbrown crystals, some of which were of considerable dimensions. They were brilliant, transparent, and harder than quartz. They were examined by MM. Thenard and Dumas.

Submitted to an intense heat in contact with the air, the crystals experienced not the slightest change, a proof sufficient in itself that they were not of the nature of the diamond. Besides, notwithstanding their considerable hardness, they were easily scratched by the latter gem. The conclusion of the academical savants was, that the pretended diamonds were merely silicates or artificial precious stones.

The experiments of Gannal gained more renown. Specimens of his productions were sent to M. Champigny, director of the workrooms of the jeweller Petitot, who examined them with care; and having satisfied himself that they scratched steel, and could be scratched by no metal, that they were of pure water, and displayed a brilliant lustre, concluded that these little bodies were nothing else but diamonds. This declaration, emanating from a man well versed in the special trade, created an excitement and even a panic in the diamond trade.

The process by which Gannal obtained his diamonds was very simple.

He introduced carbon disulphide and water into a matrass, with morsels of phosphorus, which in the disulphide dissolved rapidly. He hoped that this phosphorus would slowly absorb the sulphur of the disulphide of carbon, and that the carbon, reduced gradually to an elementary state, would crystallize.

Carbon disulphide and water will not mix together; and the former being much the most dense, occupied the bottom of the vase.

Between the two layers a pellicle formed which strongly reflected the light when exposed to it. In time this layer was augmented; and, at the end of several months it was composed of a conglomeration of little solid bodies, which were separated from the liquid by filtration through a chamois-skin. These little bodies were the crystals pronounced by M. Champigny to be diamonds-an opinion that was utterly erroneous. How they came there is not known, but it is probable that either the substances made use of were not pure, or that some foreign body or bodies had found their way into the matrass.

The man who has most effectually disturbed the slumbers of the possessors of diamonds, by agitating the question of their artificial reproduction, is M. Despretz.

This patient and persevering chemist organized a series of experiments founded at first on the belief that the diamond was formed by igneous means.

In his first attempts, accordingly, he submitted carbon to the action of the most intense heat that he could possibly command; having for this purpose united and arrayed all the Bunsen piles that he could procure at Paris, and no obtained a current of prodigious intensity.

The carbon was immediately reduced to vapour, and was soon deposited in the form of fine dust on the walls of the vessel in which it was contained. M. Despretz would have it that the carbon had been volatilized; and no one who attended his lectures at the Sorbonne can forget the profound disdain with which he would exhibit the glass globe all blackened interiorly, and exclaim, "And yet there are people who maintain that carbon cannot be volatilized!" With all due respect for this eminent opinion, it is probable that the carbon was not volatilized, using that word in its common acceptation, but that it was merely molecularly dissociated. However this may have been, the results were completely inadequate to the production of the diamond.

Violent means having failed, M. Despretz changed the system. For the currents of the pile, intense and incessant, he substituted currents of induction, intermittent and feeble; and in place of continuing their action for several hours, maintained them in activity during entire months.

The results of his new experiments M. Despretz submitted to the Academy of Sciences.

He made use of a glass vessel similar and similarly fitted up to that know as the electric egg (see Fig 89). To the lower rod he attached a cylinder of pure carbon, an inch or so in length, and nearly half an inch in diameter. To the upper rod he affixed a bundle of fine platina wires. He now exhausted the air from the balloon, and the distance from the wire to the carbon being about two inches, he then passed an inductive current by Ruhmkorff's apparatus.

The luminous arc was suffused with a red tint on the side next the carbon to a short distance from the platina; the part which enveloped the extremity of the platina wires was a violet-blue.

This disposition of the apparatus was constantly maintained; and the experiment lasted more than a month without interruption, excepting the time necessary to recharge the pile. At the completion of this time a slight black layer of carbon had been deposited on the wires. This layer, viewed through a magnifying glass, presented nothing very distinct; but to the compound microscope, with magnifying power of about thirty diameters, it offered several interesting features. Upon the wires, and especially upon their extremities, certain separate points were discoverable, which appeared to belong to octahedral crystals.

An experienced crystallographer confirmed this view, and recognized octahedrons, both black and white, the black being truncated at their extremities.

In another experiment M. Despretz fixed a cylinder of pure carbon to the positive pole of a weak Daniell pile, and a platina wire to the other pole; he then plunged both poles into slightly acidulated water. The experiment lasted two months; the negative wire or pole became covered with a black coating, but nothing was discovered in it under the microscope.

The products of the experiments were then sent to M. Gaudin to test upon hard stones. He proved, in the presence of M. Despretz and others, that, mixed with a little oil, the substance which had enveloped one of the twelve platina wires sufficed to polish in a very little time several rubies. The black powder deposited in the water served to give similar polish, but it required longer time. As it is known that the diamond is the only substance that polishes the ruby, M. Gaudin did not hesitate to consider both these substances as the powder of the diamond.

Two conclusions may be derived from the facts we have just stated; 1st, that is probable that the diamond is not of igneous origin; 2d, that M. Despretz has really obtained artificially the true diamond. This is the opinion of men of the highest authority, and in particular that of M. Dufrenoy.

The last contribution made to the interesting question of the production of the diamond was made by M. de Chancourtois. He based his theory upon phenomena presented by the solfataras, where sulphuretted hydrogen under the influence of a humid oxidization, is transformed slowly into water and sulphurous acid, and deposits crystallized sulphur. He proposed to produce upon carburetted hydrogen reactions of the same order. Under the influence of a humid oxidization all the hydrogen is transformed into water, one part only of the carbon into carbonic acid, and he thought it possible that the remainder, being slowly deposited, might crystallize and form diamonds. As a means of verification, M. de Chancourtois suggested the very slow passage of carburetted hydrogen in a mass of sand containing putrescible matter. Five years have elapsed since the expression of these views, and it does not appear that they have yet led to any positive result.