William Methold visited the mines of Golconda at a later period, and relates that at that time they gave employment to about thirty thousand laborers. The means for exploration were then exceedingly simple, and no mechanical contrivances were adopted for excavating the pits or bailing out the water. Shafts were rudely sunk in the earth to the depth of sixty or seventy feet, and the cascalho found at even that depth. It appeared to be reddish, mixed with white and yellow chalk, and was rich in diamonds. Rarely, stones of one hundred and twenty to two hundred karats were found, while those of ten to fifteen karats were quite abundant; but by far the greater number were so minute that it required from eight to twenty of them to weigh a karat.
Within the present century Dr. Buchanan and Mr. Voysey visited the mines of India, and have left interesting and accurate descriptions of their examinations and observations.
The famous mine of Pannah was examined in 1813, and found to be situated in a table-land of great extent a thousand feet or more above the Gangetic plain. The whole plain, wherever the gravelly formation appeared, afforded diamonds at various depths ranging from six feet to twenty-four. Many mines were worked in beds or borders of rivers because they were easy of access, and the lazy natives lacked the ability and means to explore the adjacent plains, which abounded in diamonds, but were destitute of the water required for washing the gravel.
The effect of the Brazilian discovery and its yield of several tons of diamonds was severely felt in Hindostan, and many of its mines were stopped in consequence. Yet there is abundant virgin territory left in India for future successful exploration, if conducted scientifically and with ample means.
The natives, with their rude methods of mining, generally ceased operations when the deposit required the removal of twenty-four feet of superincumbent soil. Hindoo labor, also, though apparently very cheap, is in reality costly when we come to compare their slow and feeble results to the efforts of well organized and conducted operations. Hence the diamond has always been a costly gem in Hindostan, and it is worth more in that country at the present time than in Europe.
Concerning the widespread idea of the reproduction of diamonds in India we will make only a brief allusion at the present time.
This theory does not seem to be of a very recent date, for the Portuguese traveller Garcias, who had been physician to the Viceroy at Goa in the early part of the sixteenth century, and who visited the mines, has left in his treatise published in 1565, some curious notes on the rapid generation of diamonds at that time. And he affirms that the soil a few feet below the surface will, in the interval of two or three years, produce diamonds again; but he also admits that the largest gems are only found at much greater depths.
Mr. Voysey, who examined the principal mines in Southern India in 1821, was also assured by the miners of this reproduction; and from his investigations he was led to adopt similar views.
Dr. Buchanan in 1813 visited the famous Pannah mine, and these views then prevailed at that locality. He examined the diamond-bearing earth, but observed nothing very peculiar in its formation. It seemed to be very red, and characterized by pebbles stained by iron and a great variety of quartz in broken fragments, chiefly white in color, or stained red in places, or dotted with black spots.
The miners who were then operating the mines assured the Doctor “that the generation of diamonds is always going forward, and that they have just as much chance of success in searching earth which has been fourteen or fifteen years unexamined as in digging in what has never been disturbed; and in fact,” he says, “I saw them digging up earth which had evidently been before examined, as it was lying in irregular heaps as thrown out after examination.”