The Glenwood post., 1910-07-16

- RAIL has practically a monop-
oily of the worlds supply of
the black diamond, while the
United States is its largest
market. 1t is found in La
Chapada and Lavras districts
of the province Of Bahia, Brazil,
where 1t is mined from river beds and
other alluyium. The miners sell their
find to agents Of exporting firms in
the city of,Bahia. 1t is calculated that
this port ships annually about $4,000
900 to $4.600.000 worth of black dia-
monds, and. with the adoption of
modern methods and machinery in
place OF the extremely primitive ones
formerly employed. the industry will
be tremendously stimulated. About
twenty-five years ago stone of LOO
carats was found. followed by one of
1.700 carats. and In 1895 gigantic
stone of 3,078 carats, or 615 grams,
which was purchased by a New York
house for $4,000 and broken up into
pieces Of suitable size for diamond
drills. At present prices this stone
would be worth about $262, 900. Dur
ing the past ten years stones of 400
to 800 carats have been discovered,
while they are frequently found weigh
ing from 100 to 200 carats.
Previous to 1870 carbonado was
practically valueless. From 1870 to
1872 it was employed as an abrasive
for cutting and polishing the white
gems. and thousands Of carats were
sold at so cents per carat, to be crush
ed to powder for this purpose. A few
years later, when carbonate was en-
ployed in diamond drilling, it sold at
from 81 to 81 carat. Between 1895
huctuated between 325 and $85 carat,
this high price being caused by the
decline in the supply of carbonado in
the past ten years, while the demand
has increased. In connection with the
subject of black diamond consumption
in drilling, 1t is interesting to remark
that in digging the drill hole at Ryb-
mix (Paruschowitz). Upper Silesia.
which attained depth of nearly 1000
feet. upward of .325.0O0 worth of car
bonado was used.
The conditions are entirely differ
ent from those of Africa. The gravel,
sand. and other material containing
diamonds lie in or near the beds Of
streams and rivers, and have been
washed down by erosion from high
"chapadas" or plateaus, which are
probably the original matrix in which
Brazilian diamonds were formed. AS
is natural. gold and variety of other
substances. such as itacolumnite,
olivine. limestone. hematite, granite,
gneiss. and clay are associated with
the diamonds. The diamond bearing
material of Brazil consists of a con-
glomerate. sometimes interbedded with
hard yellow sandstone, which is wash
ed down through erosion by rivers, or
in some cases. may be badly decom-
posed and rotten rock. Fossils are
generally lacking. The deposits often
consist of schists and schistose clay,
diamond-bearing clays. reddish earth,
granitic and gneissic formations, and
pebbles of various sorts.
The states of the republic which
have yielded diamonds are Minas
Geraes. Parana. Bahia, Goyaz, and
Matto Crosse. 1t is in the first named
that Diamantina. celebrated for the
rich diamond mines in its vicinity, Is
situated. The city is we'll built and
lies at the headwaters Of the JeQuitin-
honha. or Diamond, river, stream
$50 miles long. which empties into the
Atlantic at Belmonte. To the east of
TNa n a nt Inn 10 tho Nf
1tambe. $3.50 feet, in the Sierra Espin-
AGO Range. The mines are situated
north of Rio de Janeiro, 800 kilo-
meters. or 497 miles. north of Ouro
Preto. the capital of Minas Geraes.
The territory in which they are stu
ated forms vast ellipse. 80 kilo-
meters. or so miles. by 40 kilometers.
or 25 miles. In a plateau 1000 to 1900
meters (3.2S0 to 1897 feet), contain
ing a number of valleys cut by the
JeQuintinhonha and Its left tributaries,
Ribeirao do Inferno. Rio Caethe, etc.,
and also by the Sac Francisco's af-
|, fuents which dow to the northwest. in
a very different basin.
Although diamond mining has been
more extensively and systematically
pursued in the states Of Minas Geraes
and Bahia than elsewhere in Brazil,
Matto Crosse, Goyax. and Parana have
yielded sufficient results to justify the
belief that their future as centers of
diamond production will be prosper
GUS.
The primitive methods of mining
employed in Brazil until recent years
casve. nevertheless. abundantly re-
svealed- the natural productiveness of
the Brazilian diamantifsrons dsposits.
Two native methods are still very
largely In USE according "a. The .ooa1-