1899] THE SOUTH AFRICAN DIAMOND 179 



case it is generally associated with a little calcite, and in one place 

 with a radiating acicnlar mineral, probably a zeolite; in another the 

 calcite is mixed with a serpentinons mineral. Larger grains of iron 

 oxide appear to be wanting, and I have not observed zircon or spinel, 

 or even rntile or pseudobrookite. Some of them might turn up, as a 

 diamond might do, if more slices were cut, 1 but obviously they are not 

 at all common. The second boulder corresponds so closely in mineral 

 composition with that just described that a separate description is 

 needless. I have also examined a fragment from a third rounded 

 boulder, which when perfect must have been about a foot in diameter. 

 The rock is practically identical with that of the other two boulders, 

 but no diamonds are visible. 



Three boulders, apparently without diamonds, represent another 

 variety or species of eclogite. One is a fragment measuring about 

 7 in. x 4^ in. x 3^- in.; another an unbroken boulder, the girth of which, 

 measured in three directions at right angles, is approximately 20^- in. 

 X 19^- in. X 17^- in.; and the third is a fragment about 3 in. x 'l\ in. 

 x 2 in. In all these the outer surface is rather more decomposed 

 than in the three described above, and the same appears true of the 

 rock throughout. It obviously consists of three principal constituents, 

 with a few scattered flakes of a brownish mica. Two of them, the 

 pyrope and the diopside, do not differ from those described above, 

 except that the former is slightly pinker in colour ; the third con- 

 stituent is an altered enstatite. The mica is only moderately 

 pleochroic, resembling phlogopite ; a small grain or two of serpentinised 

 olivine (as before) may be present. Apparently the minerals have 

 formed in the following order : (a) pyrope, (b) diopside, (c) mica, (d) 

 enstatite. I had slices cut only from the first specimen, as I preferred 

 to leave the second intact, and the third was more decomposed than 

 the others. This rock obviously is closely related to the normal 

 eclogites and to the eulysites — differing from the one in the conspicuous 

 presence of a rhombic pyroxene ; from the other in containing that 

 mineral instead of olivine. If a special name be recpiired I should 

 propose Newlanclite, but personally should be satisfied with enstatitc- 

 eclogite, for I prefer to call attention to relationships rather than to 

 distinctions. 



In connection with this rock an interesting specimen may be 

 noticed, which was obtained from the blue ground. It is an 

 irregular fragment between three or four inches long, consisting of 

 crystals of a greyish-green rhombic pyroxene, in which one cleavage 

 is strongly developed, but with a barely metalloidal lustre. They are 

 approximately an inch in diameter, and between them small pyropes 

 are rather irregnlarly interspersed. As I was reluctant to injure the 

 specimen by cutting off a slice, I removed a few small flakes, which on 

 examination with convergent light proved the mineral to belong to 



1 Five were made from the first boulder, three from the second, two from the third. 



