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Page:Popular Science Monthly Volume 21.djvu/636

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THE POPULAR SCIENCE MONTHLY.

the region. The constant association of this precious stone with those minerals causes me to believe that it has been brought, like them, from the depths of the earth in the condition of a volatile compound, and that it owes its crystallization to a dissociation produced under the action of heat and a considerable pressure. Now, what is this volatile compound?

As to the oxides of iron and titanium, together with what takes place in volcanoes, the synthetic experiments of M. Daubrée leave no doubt that they have come up as chlorides and fluorides. May the case not be the same with the diamond? Its presence in the midst of a crystal of anatase lends support to this hypothesis. This is, it is true, only an hypothesis; but it is an hypothesis based on the observation of phenomena in which I have taken analogy for my guide. Far be it from me to assume that I have resolved the problem. I shall be well satisfied if I shall ever be able to raise the corner of a veil which more fortunate and more skilled men than myself will, I am convinced, eventually remove completely.

It is very difficult to estimate the quantity of diamonds furnished by Brazil. Between 1772 and 1793 the royal treasurer received 877,717 carats of diamonds, or about 38,000 carats a year. At least as many more were stolen or smuggled away. This would make the annual production in round numbers about 80,000 carats; if we assume this average for a total period of a hundred and fifty years, we reach the figure of 12,000,000 carats, or nearly 2,400 kilogrammes (6,000 pounds), or a volume of seven or eight hundred quarts. It is impossible to calculate even approximately the total value of these stones. Generally, the diamonds of Brazil are small; stones of fifteen or twenty carats are rare; and the Star of the South, a stone which was found in the western part of the province, at Bagagem, is the only one of them that calls for a special mention. This diamond weighed, in the rough, 254·5 carats, and, after being cut, 125 carats. Finds like this are very rare; and I know of miners who have washed and washed over the cascalhos of Bagagem for twenty years, without having found a second Star of the South, or even a single diamond of value. They are still, however, far from giving up the search. The total production of Brazil in 1880 hardly exceeded sixteen kilogrammes, or forty pounds (about 80,000 carats). In the same time, the mines of the Cape yielded 2,000,000 carats. The Brazilian diamonds, however, have a very marked superiority in luster and beauty, so great that they have often been taken for Indian brilliants.