The daily morning journal and courier., 1899-06-21
THE ORIGIN OF DIAMONDS.

l LIE oINlblIN CI LIAM
 The dispute among geologists as to l the origin of the diamond seems to have 1 been settled by Prof. Bonney in paper read before the Royal Society yesterday afternoon, In the localities from which the previous supply had been drawn, | both in India and Brazil, the gem oc- cured, like a pebble, in certain gravelly | materials, but had not been traced back to any rock that gave an indication or | it's genesis. But soon after the dlscoV- | cry of diamonds in river sands on the | Orange and Vaal rivers in South Africa, l they were found in a peculiar material, 1 not of superficial character. At first extremely incoherent, and of q broWnish | buff color it assumed, as the miners dug deeper, a dull dark greenish or bluish tint. and became harder. In this stuff, which they called yellow ground and "blue ground" according to it's color, lay the diamonds, together with several other minerals, such as garnets, various iron ores, oivine, augite, and It's allies.
 Digging was begun nearly thirty wears ago, at first unsyetematically; but from these early efforts, the great damond-mining industry has been de- veloped and the excavations have been carried near Kimberly, to a depth of more than fourteen hundred feet. Here the rock has become so much more sol- i'd that 1t is at firet about as hard as or dinary limestone. The blue ground is only found in limited areas, generally rather circular in outline which are aJf IT tho some of the most famous are several acres in extent being in the immediate neighborhood of Kimberley The rocks around them are of dark shalee, banded with hard sandstones, in which sheets or dykes of basalt or some material once molten are occasionally found The blue ground fills a sort of huge ehaft fin these other rocks, and is itself some times cut by regular dykes. Thus, it reminded geOlogists of necks of extinct volcanoes, such as may have been seen among the coal bearing strata of the Fifeshire coast
 That the diamond was an inmate of the blue ground could not be doubted: but how did it get there, and what was the true nature of the rock? On this l, some thinking that the gem had been produced where it now lay; others that it had been formed in some older rock which had been shattered by volcanic explosions. Many of the minerals as- sociated with it looked as if they had been thus derived, and it was some- times broken. The blue ground fre- quenty contained fragments of the ad- jacent country rock; but this did not quite clear up the mystery; for some- times a molten material, in breaking through other rocks. catches up bits of them, and, whatever was the origin of the matrix, as it is rather porous tho diamond might have been subsequently produced in it by such an agent as hot water.
 The mystery has now been cleared up by discovery at the Newlands Mines, | West Griqualand, rather more than forty miles from Kimberley. About two | years ago, Mr. Trubenbach, the com- | panys manager, accidentally picked up | specimen in which small diamonds | were apparently imbedded in a garnet. | His curiosity once aroused, everything | was collected, and among these things certain boulders containing garnets which now and then occurred in the blue" even two or three hun dred feet under ground. Afterwards