The Anaconda standard. [volume] (Anaconda, Mont.) 1889-1970, 1899-08-27
SOME FACTS ABOUT DIAMONDS.
Where They Originate and When They
Were First Discovered.

We're First Discovered.
The dispute among biologists as to
the origin of the diamond seems to have
been settled by Professor Bonney in a
paper read recently before the Royal
society. In the localities from which
the previous supply had been drawn,
both in India and in Brazil, the gem
occurred, like pebble. in certain grav-
ely materials, but had not been traced
back to any rock that gave an indica-
ton of its genesis. But soon after the
discovery of diamonds in river sands
on the Orange and Vaal rivers, in
South Africa, they were found in a Pc
culiar material, not of a superficial
character. At first extremely incoher-
ent and of a brownish buff color, it as
sumed, as the miners dug deeper, dull,
dark greenish or blush tint and be-
came harder. In this stuff, which they
called yellow ground" and blue
ground according to its color, lay the
diamonds, together with several other
minerals, such as garnet, various iron
ores, olivine, augite and it's allies. Dig
ging was begun nearly 80 years ago,
at first unsystematically, but from
these early efforts the great diamond
mining industry has been developed.
and the excavations have been carried
near Kimberley to a depth of more
than 40 feet. Here the rock has become
SO much more solid that it is at first
about as hard as ordinary limestone.
The blue ground" is only found in
limited areas, generally rather circular
in outline, which are spotted irregu-
larly over the country, some of the
most famous, which are several acres
in extent, being in the immediate
neighborhood of Kimberley. The rocks
around them are of dark shades, band
ed with hard sandstones, in which
sheets or bikes of basalt or some ma
terial once molten are occasionally
found. The blue ground fills sort Of
huge shaft in these other rocks and is
itself sometimes cut by similar bikes.
Thus it reminded biologists of the rocks
of extinct volcanoes, such as may be
seen among the coal-bearing strata of
the Fifeshire coast. That the diamond
was an inmate of the blue ground could
not be doubted, but how did it get
there and what was the true nature of
the rock? On this point biologists
adopted different views, some thinking
that the gem had been produced where
it now lay, others that it had been
formed in some older rock which had
been shattered by volcanic explosions.
Many of the minerals associated with it
looked as if they had been thus derived
and it was sometimes broken. The
blue ground frequently contained frag-
ments of the adjacent country rock, y
mystery, for sometimes a molten ma
terial in breaking through other rocks
catches up bits of them and, whatever
was the origin of the matrix, as 1t is
rather porous, the diamond might have
been subsequently produced in it by
such an agent as hot water. This mys-
terry has now been cleared up by dis
covery at the Newlands mines, West
Griqualand, rather more than 40 miles
from Kimberley.
About two years ago Mr.. Trunen-
bach, the company's manager, acct
dentally picked up specimen in which
small diamonds were apparently imbed-
ded in a garnet. His curiosity once
aroused, everything remarkable was
collected, and among these things GER
tain boulders containing garnets which
now and then occurred in the blue
even 200 or 800 feet underground At
terward one of these was found to show
diamond projecting from the surface.
The boulderS were broken and were
found to contain others. Afterward a
diamond was seen on a second specl-
men The rock is one which, though
not very common, is well known to
biologists 1t bears in science the name
of eclogite and that from NewlandS
consists almost exclusively of red
garnet and a rather peculiar light green
augite. The rock is coarsely crystalline
a molten condition, the diamond being
one of its original constituents. But
this discovery also settles the true ma
ture of the blue ground" and that 1t
was not the birthplace of the diamond.
These boulders are evidently water
worn and must have been fashioned in
a past geological period from some
much more ancient rock, now buried
out of sight. They must have reposed
for ages in an ancient gravel at the
very bottom of the sedimentary rocks
of the district-rocks which are about
as old as the red marls of the English
midlands. Eventually the everything
materials and some of the shattered
rocky floor in which the diamonds are
imbedded and of which these boulders
are only samples were sent flying by
volcanic explosions. 1t was in this way
that the diamond bearing blue
ground" was found.-London Standard.