1899] THE SOUTH AFRICAN DIAMOND 177 
with, or indenting, or actually embedded in a fairly large, somewhat 
irregularly shaped pyrope. The one specimen came from Kimberley ; 
the other from the Newlands Mines, West Griqualand, and it was found 
by Mr. G. Trubenbach, the managing director in England of the 
Company, during a visit to South Africa. 
In these mines, as in the De Beers Mine,' rounded boulders occa- 
sionally occur in the diamond-bearing rock—the blue ground (soft or 
hard, as the case may be). Mr. Trubenbach brought some of these 
from the former locality to England, and a small diamond was then 
’ observed to be exposed on the surface of one of them; the boulder was 
broken and others were disclosed. One fragment was sent to Sir W. 
Crookes, to obtain the benefit of his opinion, and he showed it to me. 
Though I saw it by artificial heht, I felt certain that the rock was not 
any variety of the breccia, but a true eclogite, and expressed that 
opinion. He most kindly asked me to examine the rock, and obtained 
from the directors permission for me-to cut off as much as I thought 
necessary for a satisfactory investigation. I am deeply indebted to him 
for this kindness, and to Mr. Trubenbach for aiding me with other 
specimens from the mines and responding so willingly to my inquiries. 
An account of my examination of the whole series was communicated 
to the Royal Society on 1st June,’ and the following are the principal 
results :— 
The boulders of eclogite were six in number, but all prior to 
fracture had been well rounded. Stones of similar shapes might 
readily be found in the bed of an Alpine torrent after a course of 
several miles — in other words, I am sure they are water-worn. 
Three are of one species of eclogite, and three of another; two of the 
former being known to contain diamonds. That in which this mineral 
was first discovered is apparently from a quarter to a third of an ellip- 
soidal boulder, its axial measurements being roughly 4 in. x 3 in. x 2 in. 
The other specimen, probably about a quarter of the original, measured 
in the same way about 54 in. x 5 in.x 34 in. The outer surface of the 
former specimen is smooth; the pyropes ® barely, if at all, projecting. 
So it has been in the other, but the surface now is slightly corroded. 
Near the exterior the pyropes, as is often the case, are covered by a 
dark outer film, thicker than the thumb-nail, but this is hardly per- 
ceptible near the centre. 
The first-named specimen is comparatively rich in diamonds. 
Two are visible on the smooth outer surface, a third on one of the 
fractured faces, and seven on the other, but two of these (partially 
? The occurrence of boulders in the blue ground of this mine (among them granite and 
eclogite) was mentioned so long ago as 1893 by A. W. Stelzner, Sitzwngber. u. Abhandl. 
der Isis, Dresden, 1893, p. 71. 
2 Proc. Roy. Soc. London, 1899. 
* I follow previous writers in applying that name to the red garnet of this rock and the 
washings. Its accuracy is confirmed by the fact that magnesia-mica is so abundant in the 
kelyphite rim. 
12—-wnar. sc.—von. xv. No. 91. 
