8 ON A DIAMOND-BEARING PERIDOTITE AND
diamond
exhibit at the Colonial Exhibition, I have been able to examine. They
come from De Beers Mine, and having been found at a greater depth and
in a much less decomposed condition than the specimens primarily
examined, it has become possible now, for the first time, to determine
the exact nature of the matrix of the diamond.
The
rock occurs in two types, one not bearing diamonds, the other
diamantiferous, and the distinction between them is suggestive. Both
occur in the same mine, and are dark, compact, heavy rocks, closely
resembling one another, and differing mainly in the fact that one is
free from en-
