its rough form, a diamond is a lusterless, translucent
crystal that resembles a chip of broken glass. For it
to be transformed into a jewel, it must be cut into
a particular gem shape and then polished, facet by facet.
When Sir Ernest Oppenheimer organized the diamond cartel,
there were no machines that could cut and polish diamonds.
The crucial transformation from rough stones to jewels
had to be done by hand, and only a relatively few craftsmen,
mainly in Antwerp and Amsterdam, possessed the necessary
skills. Oppenheimer therefore set out to extend the
control of the cartel to diamond cutting as well as
to diamond mining. He realized that although outsiders
might conceivably discover new sources of diamonds,
they could not compete with De Beers unless they also
had the means to cut diamonds. The art of diamond cutting
was thus ingeniously incorporated into the diamond invention.
Until the late fifteenth
century, diamond cutting had been a primitive business.
Diamonds were first "cleaved" by placing a chisel at
the stone's weakest point of molecular cohesion and
striking it with a mallet. If the precise point was
located on the diamond's structure, the adhesion would
be so weak that the diamond could be separated with
a fingernail. If pressure was applied to the wrong point,
or in the wrong direction, the diamond would shatter.
After the medieval cutter succeeded in cleaving the
diamond into the basic shape of the desired jewel, he
placed it in an egg shaped tin cup, called a dop, and
attempted to remove any imperfections in it by striking
it with another diamond, since only diamonds were hard
enough to cut diamonds. This process, which was extremely
slow and painstaking, was called bruting. Even though
the medieval cutter could eventually give the stone
a jewel like appearance through these methods, he was
extremely limited by the natural shape of the diamond.
The situation suddenly
changed at the end of the fifteenth century when a Jewish
diamond cutter in Antwerp named Lodewyk van Berken invented
the scaif. The scaif was simply a polishing wheel that
was impregnated with a mixture of olive oil and diamond
dust, but it completely revolutionized the art of diamond
cutting. The rough diamond was clamped in a dop and
held against this whirling disc, while the diamond dust
on it ground away the diamond to the desired angle.
With the scaif, it became possible to polish symmetrically
all the facets of the diamond at angles that reflected
the maximum amount of light. As disciples of Van Berken
applied the laws of optics to these angles, they created
sparkling gems that fascinated the princes and aristocrats
of Europe. Charles the Bold, Duke of Normandy, became
the patron of Van Berken and commissioned him to cut
a 137-carat diamond, which became known as the Florentine.
Diamond cutters from
all over Europe came to Antwerp to study Van Berken's
methods, and orders for these light reflecting gems
flowed in from all the royal courts, making Antwerp
the pre-eminent diamond-cutting center in the world.
At the head of the Pelikenstrasse, the street that winds
through Antwerp's diamond district, is a bronze statue
of Van Berken dressed in a jerkin and skull cap, with
a holster full of diamond tools strapped across his
waist. He holds in his right hand a diamond.
The next major innovation
came in the twentieth century with the invention of
the diamond saw. Cleaving diamonds, although an economic
and efficient process, had limited cutters to shaping
the stone according to its natural lines of cleavage.
The diamond saw, a circular steel blade lubricated continually
with oil and diamond powder, allowed the cutters to
go against the grain of the diamond without shattering
it. The diamond saw, moreover, allowed cutters to salvage
jewels from badly misshapen and deformed diamonds. To
be sure, sawing was a more expensive process than cleaving.
It required about one-tenth carat of diamond dust for
every carat of diamond sawed through. And it was also
a much slower process than cleaving a diamond with a
single stroke. Indeed, it took days to saw through a
two-carat diamond. Despite such disadvantages, the diamond
saw became t he common method of shaping diamonds in
the postwar years. Since it was far easier to train
workers to saw than to cleave diamonds, it quickly transformed
diamond-cutting in Antwerp from an esoteric craft to
a semi-mechanized machines to polish diamonds.
The final refinement
of the process for cutting diamonds came in 1919 when
a twenty-one-year-old mathematician named Marcel Tolkowsky
calculated the formula for the ideal proportions of
a cut diamond. Master cutters had achieved an inner
light in diamonds by choosing angles that sacrificed
some reflected light in order to get refracted light.
They did this by relying mainly on intuition, trial
and error, and experience. Tolkowsky's formula gave
the optimum ratio between the angles of facets opposing
one another in a diamond. Following this formula, a
cutter would achieve the maximum refracted (or "inner")
light with the least sacrifice of reflected (or outer)
light. This formula led to the popularization of the
so-called "brilliant cut" diamond, which had fifty-eight
facets polished exactly to the tolerances of the ideal
With the reduction
of diamonds to a mathematic formula, it became possible
to devise semi-automatic machines to polish diamonds.
In the early 1960s, a De Beers subsidiary introduced
the Pieromatic diamond-cutting machines in Antwerp.
Although these machines still required trained workers
to guide diamonds through the polishing operation, they
greatly reduced the need for master craftsmen or even
long apprenticeships. According to the literature accompanying
the Pieromatic machines, men could be trained to operate
them in a matter of months.
As the diamond business
expanded in the postwar years, Sir Ernest Oppenheimer
made every effort to keep the cutting industry anchored
in Antwerp. Not only was Antwerp just across the channel
from England, and highly convenient to De Beers, but
Sir Ernest considered it essential to maintain a special
relationship with the Belgian government, which controlled
the huge diamond deposits in the Congo. Under his express
orders, Monty Charles provided the Antwerp diamond cutters
with ample supplies of diamonds at the London sights
while cutting back on supplies to their competitors.
Amsterdam, which had
been a major diamond cutting center in the nineteenth
century, gradually lost almost all its gem cutters to
Antwerp. (Strict working conditions imposed on the Dutch
diamond-cutting factories by the labor unions greatly
accelerated the exodus in the prewar years.) But, despite
all of De Beers' efforts, Antwerp did not achieve a
monopoly on diamond cutting. The larger and more expensive
diamonds were sent to be cut directly to New York, in
order to avoid paying the tax on finished jewels, while
the smaller diamond chips were sent to India to be polished
by cheap labor. The "melees," or medium-sized diamonds,
generally under a half carat in weight, tended to flow
to Israeli factories. Nevertheless, Antwerp's cutters
continued to receive most of the valuable diamonds and
virtually all the difficult-shaped diamonds that required
To see how these diamonds
were cut, I visited the Trau Freres factory in Antwerp.
Founded in the nineteenth century, Trau Freres specializes
almost exclusively in cutting a triangular-shaped twisted
crystal known in the trade as a "macle." As Trau Freres
is invited to De Beers' sights in London on a regular
basis, it receives all its macles from De Beers. The
factory employs about 100 workers, who receive on the
average a salary and benefits of $400 a week, which
makes them among the highest paid workers in Europe.
Each worker was seated in front of a table cutting and
polishing an individual macle.
The diamond I watched
being shaped at Trau Freres started out looking like
two triangles folded into one another. It took about
ten hours for the craftsmen to saw it into its basic
shape, which resembled a valentine heart. The heart
shaped stone was then placed in a cup-like dop and rubbed
against a second diamond in order to wear away the sharp
and irregular edges. Finally, the craftsman began polishing
the individual facets of the diamond on his whirling
scaif. By the time this arduous process was completed,
the diamond would have lost at least 40 percent of its
original weight. This particular diamond had weighed
io carats when Trau Freres received it in their box
at the London sight, It cost them $4,000, or $400 per
carat. The labor and interest costs on this individual
diamond amounted to about $1,000. The final heart-shaped
diamond that was cut weighed only 6 carats.
To break even, Trau
Freres would have to sell it to a wholesaler for at
least $ 5,000, or $ 837 per carat.
The thin margin of profit
for specialty diamond cutters like Trau Freres depends
almost entirely on the price they pay the Diamond Trading
Company for the uncut diamonds in their box at the sights.
If De Beers elects to raise the price even slightly
or to provide them with an inferior selection of diamonds,
these specialty cutters would be forced out of business.
And according to at least one Antwerp specialty cutter,
De Beers still uses its leverage over these cutters
to prevent them from cutting diamonds from independent
mines. By controlling the activities of these few cutters,
De Beers makes it extremely difficult for any independent
mine to sell the full range of its diamonds. Rather
than forgo the profits from these poorly shaped diamonds,
most potential competitors have been forced to sell
their entire production to De Beers or one of its many
subsidiaries. De Beers thus turned diamond cutting into
an important element in its diamond invention.