The Marion daily mirror. (Marion, Ohio) 1892-1912, 1909-11-22
THE BLACK DIAMOND
II Is One OF the euriosities Of the
Mineral Kingdom.
A PUZZLE TO SCIENTISTS.
Nature Has In Some Peculiar Way
Produced This Rare Form Of Carbon
and Then Thrown Away the Secret
Of the Procoss---Found Only In Brazil.

times joklngly applied to ordinary coal
which we burn III our furnaces. but
the real "black diamonds" of com
merce are among the most unique min
eral products of the world, aud they |
serve n purpose In the Industrial world |
that makes them of great value. The |
black diamonds are pure carbon aud |
yet in no outward appearance rcscm- /
BILE the diamonds which we arc accus- |
are slightly harder than the crystal or /
gen diamonds aud, in fact, about the /.
hardest substance known.
Black diamonds, or carbOns. are
among the greatest curiosliies of the
mineral Kingdom. They are without
crystalline form and are found in ir-
regular pieces, ranging in size from
half carat up TO three. four and five
hundred carats. They are dark gray,
black or brownsh in color and opaque.
The real diamond of the iewclry trade
is also pure carbon, but translucent
and crystalline in form. Two objects
so alike in composition could not bc
found so opposite in appearance as
these two forms of carbon.
Another peculiar thing about the
black diamonds is that they are found
only in one locality in the world. They
come from very small section OF Bra.
I'll not more than 22j miles square In
area. Outside OF This limited territory
no pure black diamonds have ever
been found.
What peculiar freak of nature caus
cd the deposition OF the black dia-
monds IN this section of the world and
nowhere else is one of The mysteries
which science has failed TO explain.
None of them has been found in the
great Kimberley diamond regions.
where the crystal form of diamonds
have for so long been mined
The whole origin of the black dia.
mond Is. therefore. a scientific enigma.
Naturally the question Is raised. "Of
what use Is black dinmoudT No
one would care 10 wear one of these
diamonds. which resembles n piece Of
coal more than II real diamond. aud So
/ far no one has popularizcd tho black
gems rs the black pearl has been,
! Nevertheless the black diamonds serve
most important and useful function
In the industrial world,
/ This pure black carbon is not onl,'
/ harder than the real diamond. hut
! tougher aud not soebrittlc as the gem.
Consequently il isfcf great value FOR
many mechanical pulposes and parllC'
uarly for boring With diamond drills.
In diamond drilling the tips of the
! drills are studded with carbon. or
! black diamonds, and when the borcs
| are deep the pressure is SO great that
| the gem diamonds would bc crushed in
the process But the carbon rcsists
this continued pressure and slowly
/ eats down into the rocks.
In diamond drill work the carbon is
set in circular pieces of soft steel or
! iron, called bits. and these bits are at.
tachcd TO tubing. Armed With these
black diamond teeth. the drills pusl,
/ their way down under severe pressure
! TO a depth of five and six thousand
| feet, cutting through the hardest kiuI
of rock. Some black diamonds are
much harder than others, and tbcrc is
no way TO determine by the color the
difference in the degree of toughncss,
! Black diamonds or pure carbon arc
not by any mcaus cheap. and the own.
ers Of the mines In Brazil where they
| are gathered are making good thing
out of their monopoly There is no
known substance that can take tho
! place of carbon in drills in boring for
| gold. silver. copper aud other mineral
deposits Before the black diamonds
of Brazil were discovered II was inl'
possible TO make borings
When the carbon was first inrodu,
ed in our industries it was used in
diamond saws for cutting stones mar
BILE aud similar substances. Then tue
price advanced so that the carbon was
found too costly FOR such use. and bort
was substituted for stone cutting. Bort
is really an imperfect crystal OF gem
diamond but Il is too brittle for use
In drills. Consequently bort has TAX,
en- the place of black diamonds foI
stone cutting, aud the latter have been
restricted almost entirely TO diamond
drilling purposes.
The average size OF black diamonds
used Ia the drills ranges from two IL
Ave carats. but the larger specimens
give much better results. They cost
more. but they last longer Conse
quently there Is greater demand foI
the larger pieces of pure carbon. and
the price is sometimes run up to pre-
MUM figures FOR unusual specimens.
Tho fear that the supply of black
diamonds may some day give out and
pnralyze the diamond drilling industry
has stimulated prospectors 10 syste
matte search for new deposits. but NJ
far they have not been successful OF
the other hand, scientists have beeI
making close study of the chelnica
conditions which have produced the
black diamonds but their manufacture
Is apparently about as ditlicult as tho
making OF the gem diamonds, 1t ii
possible under certain conditions Il
make either, but not in sizes sufilclen
to be Of any commercial value. Ma
ture IN some peculiar way has made
these rare products and then thrown
the secret OF the process away. IL any