328 THE DIAMOND MINES OF SOUTH AFRICA
allowing
the solution to evaporate, this hydrocarbon was separated and found to
be crystalline, strongly aromatic, volatile, burning with a smoky
flame, and melting at 500 C.
"
That the rock was a true igneous lava and not a mud or ash is indicated
by the fact that the minerals and their associations are those
characteristic of eruptive ultra-basic rocks." He gives several other
reasons for having formed this opinion ("The Matrix of the Diamond,"
page 52). Professor Lewis further states that "the Kimberlite is shared
by no other terrestrial rock. In structure it resembles meteorites of
similar composition. If the ground-mass of Kimberlite were replaced bv
native iron, it would be nearly allied in both structure and
composition with meteorites known as Chondrites."
Rock similar to Kimberlite. —
Mr. Arthur W. Rogers, geologist to the Cape Government, informs me that
during the year 1903 he examined some volcanic pipes in the Cape Colony
which were in many respects like the Kimberley pipes. Some of them were
filled with melilite basalt in close connection with a breccia similar
to the blue ground at Kimberley. He thinks that these pipes point to
the age of the Kimberley mines, which he believes to be of the
cretaceous or later age.
In
Bohemia a rock occurs which contains every mineral known in the blue
ground of Kimberley. I was shown by Dr. Stelzner two cases containing
these minerals, and, in every instance except one, the Bohemian
minerals corresponded with those from Kimberley. I had previously
presented the Mining Academy at Freiberg with a few small diamonds
which were in the collection of Kimberley minerals, but the
corresponding box in the Bohemian case was empty.
The
conclusion that one may draw from this is that Kimberlite does not
always carry diamonds, and I am borne out in this conclusion by the
fact that there are numerous pipes resembling those at Kimberley in
every respect, except that they contain no diamonds.
Occurrence of Diamonds in America. —
The occurrence of diamonds in many of the states of North America is
well authenticated. The largest of these weighed 23^ carats, and was
found near Richmond in the state of Virginia. It is an off-colored
stone and of no great value.
It
is a remarkable fact that in many of the districts where alluvial gold
is found, diamonds occur. In North Carolina, South Carolina, and
Georgia numerous diamonds have been found in the alluvial gold
diggings. In California in many of the counties where placer and
hydraulic gold mining has taken place, diamonds have been found. The
author can
