“The base of the rock[27] consists of the same ingredients as that described above, the mass of it being the hydrated bronzite. The rock is further very full of fragments of the shale, which has been altered, but still contains carbon; indeed the character of the rock is almost that of a breccia, in which these masses of shale are cemented by hydrated bronzite containing the vaalite and the bright green bronzite, with ilmenite and the other minerals associated with it.... The several minerals composing the rocks, exhibit this undoubtedly once igneous rock in the light of a bronzite rock, converted into a magnesium silicate, which has the chemical character of a hydrated bronzite.... The steatite like magma in which the other minerals and shale fragments are contained may have originated in an augitic mineral, but this is not very probable. The alterations that have ensued from the shattering of the eustatite rock, at a period subsequent to its becoming solidified, having aided in effecting the hydration that has so largely changed it from an eustatite rock into a mixture of eustatite with a hydrated eustatite, a combination which, both in its composition and structure, recalls vividly to the mind the similar mixture of the former mineral with the so-called pseudophite in which it occurs at Zdar, in Moravia.” From the foregoing description a fair idea may be arrived at of both the formation and appearance of this mine, which may fairly lay claim to be one of the wonders of the world. In the next chapter I will give the principal theories concerning the origin of this mine. [Illustration] CHAPTER XI. SOURCE OF DIAMONDIFEROUS SOIL.—EXTRACT FROM MESSRS. BAIN, URE, DANA AND OSBORNE’S GEOLOGICAL THESES.—VARIOUS THEORIES ADVANCED—NONE ENTIRELY SATISFACTORY OR CONCLUSIVE.—THE ORIGIN OF THE PRECIOUS STONE VEILED IN MYSTERY. The extracts in the previous chapter, taken from the papers of the afore-mentioned mineralogists, show, there can be no doubt, that the diamondiferous soil of the diamond mines of South Africa is, for the most part, the débris of an igneous rock; but little or no idea is given how the mines became filled with the soil. Although I am unable to throw any additional light upon this very difficult subject, I nevertheless am of opinion that this chapter would be incomplete without giving a few more extracts from previous writers. I may mention, however, that scarcely a sufficient number of facts have as yet been gathered to enable geologists to offer any theory of the formation of the diamond mines that will carry conviction with it.