“Kimberlite” and the Source of the Diamond in South Africa

Abstract

THE origin of the volcanic pipes of South Africa and the genesis of the diamonds contained in their “blue-ground” filling are as productive of controversy as that other geological puzzle—the source of the gold in the Witwatersrand conglomerates—the discussion of which was revived by Prof. J W. Gregory at a recent meeting of the Institute of Mining and Metallurgy; and agreement among the disputants is as little likely to be arrived at in the one case as in the other. Quite a crop of papers on the diamond-pipes has recently appeared,¹ and a perusal of these reveals so remarkable a variation of opinion that it may perhaps serve a useful purpose to give in these columns a brief summary of the different views as to the nature of the original matrix of the diamond and the place in which it was produced, that have been put forward from time to time since the discovery of the “dry diggings” at Kimberley in 1870.