It has been asserted that the diamond has been found embedded in the singular quartzite to which Count D’Eschwège gave the name of itacolumite, but we are inclined from examination of one of these specimens to think that its presence is quite accidental. In the State of Georgia there are immense beds of itacolumite, appearing, also, here and there along the auriferous formation which extends from Virginia to central Alabama; and they afford ample fields for proof of the statement that the mineral is really the true matrix of the gem. But, after careful examination of some of these exposed rocks, we are led to regard the itacolumite as an associate mineral to the diamond, and that any farther connection with the gem is very distant. Fragments of this rock are quite often found together with quartz in the conglomerate; but we do not regard their presence as essential as that of a ferruginous oxide, which is one of the distinguishing features of all gem mines, and especially of the famous deposits of Ceylon, where the diamond is never found. The best and most characteristic mines of India, Brazil, and Africa are situated on elevated plateaux, where there is at present but little vegetation. To give the reader an idea of the formation, we will describe one of the districts of South Africa, which may serve to illustrate all others. At Pnict Kopje, in the Vaal region, the diamonds are found on an elevated plateau one hundred and fifty feet above the river bed; and many of them have been discovered but two or three feet below the surface, in company with fossil wood and even bones. In the Orange River Republic they occur frequently in peculiar isolated and circumscribed spots, called by the miners “pans.” These are basin-like hollows which are filled with water during the wet seasons. In these pans none of the diamonds exhibit signs of abrasion caused by shock or attrition, although the quartz pebbles forming the gravel and conglomerate show in their rounded angles evidences of aqueous action. The gems are not only found in the shallow edges of these hollows, but are taken from depths of one hundred feet and more. And they are always found in their peculiar and connected conglomerate, which seems to have formed at the bottom of some pool or lake. Hence we may explain the superficial depth of the cascalho at the shores of the extinct pond, and the increased depth at central parts of the fields. If motion had taken place among the pebbles forming the conglomerate after the deposition of the diamond, we might properly look for worn surfaces on the gems from shock with contact with loose rocks; for slight blows will mar the surface of the diamond, even if its edges scratch all other minerals with perfect ease.