The San Francisco call., 1908-11-22
REQUIRES MONTHS
TO CUT BIG STONE
First the Cullinan Diamond Is
Cleft Into Three Pieces
With Knife

Consul Henry II. Morgan of Amster-
dam furnishes the following informa-
tion concerning the polishing of the
great Cullinan diamond:
AS the work of polishing progresses
to completion great interest attaches
to the Cullinan diamond, although sew
eral months will elapse before it will
be completely finished. There has been
a great deal of secrecy connected with
the polishing of this stone but l have
been able to obtain certain facts in
connection Herewith which may be of
general interest.
The delicacy OF the work undertaken
by the polishers in the execution of
this work can not be realized. 1t was
necessary in the first instance to cleave
the stone In three pieces in order to
remove two very bad flaws therein.
This cleaving is done by first making
an incision into the stone with dia-
mond cutting saw at the point where
1T is to be cleaved and following the
grain Gas all diamonds have a grain
as wood has) to depth of one-half
to three-quarterS of an inch. Before
this cleaving operation was undertaken
crystal models were made and cleaved,
in order to ascertain, as far as could be
known. Just what would happen when
the same process was applied TO the
real stone.
SPLITS THE STONE WITH KNIFE
After the incision was made the
cleaver inserted into the slit a spe-
cially constructed knife blade made of
steel rod struck il a hard blow and
cut the stone in twain exactly at the
point where 1T was proposed it should
be cut. 1t was an exceedingly well
executed piece of work. 1t must not
be overlooked that the cleaving of a
diamond is not always done along the
line it is intended, and 1t not infre
quently happens that in cleaving a
stone 1t flies into great number Of
pieces.
The stone having been successfully
split. the next and final operation is
the polishing thereof. and this process
idea of the hardness of diamonds II
may be interesting to state that the
disk on which this diamond is being
polished, which is made of cast iron
and steel. revolves at a rate of 2,400
revolutions per minute. The diamond
is pressed down on this disk, which is
literally supplied with mixture Of
diamond dust and oil. by weights OF 15
TO 20 pounds. and the disk will con-
stantly turn from Z a. m. to 9 d. m. in
cluding Sundays, for 10 to IL months
before the polishing operation will be
completed.
It has not yet been positively decided
in what shape the stone will be fin
ished. but the general impression is
that it will be pear shaped. II will be
when polished. many times larger than
the Excelsior. which was up TO the dis
covery of the Cullinan the largest dia-
mond in the world. The CulIinan
"
The part of the stone which is on the
mill will possibly be given So facets.
which is the number given to all other
diamonds of whatever size. and it will
weigh. when finished, between 500 and
500 caratS-
HAS A VALUE OF $2,5O0,0OO
The actual commercial value of the
completed stone will be about $2,500.-
600, but it's unique character will pos
sibly make it priceless.
When the Cullinan was found about
three years ago 1t was problem OF the
Premier company as to what DISPOSE
tion could be made of il. It's mere
size, weighing as ii did something over
one and a nalf pounds. made il unnnar-
ketable and unstable. and to cut il
up into small pieces would destroy. to
a large extent, not only its intrinsic
but its sentimental value The dia-
mond hence remained in the vaults Of
the Premier company for nearly three
years, when it was decided by the
Transvaal government to present IL to
the king of England on the anniver-
sary of his sixty-sixth birthday In
the rough the stone was valued at
about S1,000,0O0. and about this price
was actually paid therefor, viz, $500
600 in cash and 100000 representing
so per cent of the interest they had
therein, on account of the fact that
the government is entitled to this per-
centage of the output OF all diamond
mines in South Africa 1t will possibly
be ready for delivery within seven or
eight months.