Tuesday, February 15, 2011

Cutting and Polishing Diamonds

India has always been regarded as the natural and ancient home of the
diamonds. Up to 1728 the whole world's supply of diamonds was found in the
Deccan plateau in the valleys and on the beds of streams to a depth of
twelve to sixteen feet of earth. Placed there by the Gods as a gem endowed
with magical qualities, Indians revered tyhe diamond as far back as 1500 BC,
the age of the Vedas.

During those ancient times, diamonds were not cut. The rough stones were
mounted as such in jewellery, in helmets and on swords. This is why Indians
who wrote on gems, such as Buddhabhatta, Thakkura Pheru describe the shape,
and nature of rough diamonds in great detail. For example, Thakkura Pheru
wrote in 1315 AD: 'The best rough diamond has symmetric facets, prominent
solid angles, very sharp edges, of the first water, free of impurities,
sparkling, flawless and light in weight.'

Being the hardest known mineral in nature, only diamonds can cut or abrade
other diamonds. Artisans used this property to best advantage; they rubbed
one diamond against another for months to get the shape they wanted. They
were expert in the art of grinding and polishing diamond crystals and kept
gemstone shaping a family secret, not to be revealed to the outside world.
It is likely that their techniques dated back thousands of years, but there
is hardly anymention of this in Indian Literature. Ancient texts state that
while the diamond was extremely bhard and indestructible, it could easily be
split by a light blow along certain directions and that the earliest diamond
workers employed such techniques to remove heavy flaws and cracks and to
smooth the faces of crystals. Kautilya in his Arthashastra wrote of the
ability of diamonds to scratch hard metals an other gemstones. It is
possible that Indian wworkers tried to cut and polish diamonds with other
diamonds as early as 77 AD, engravers embedded diamond fragments in iron to
make cutting tools. According to Pliny,these tools could in turn cut
diamonds. During his travels in India in the eighteenth century Tavernier
who wrote extensively on the gemstones industry in the country, found
artisans in India were using iron wheels with diamond grit to remove flaws
in diamond crystals. At the time of his visit, most Indians were merely
polishing rough stones that had regular crystallised shapes. Faults like
inclusions and grains were removed by grinding, but deep faults were sought
to be hidden by a great number of small facets. Some European workers who
had practised diamond cutting in Europe but had settled in India were given
the larger and more expensive stones for cutting. They were better at this
work perhaps because they had already attained a higher level of perfection
in their work. It has been recorded that as early as 1375 AD, diamond
cutters in Germany were active and had even formed a guild in Nurenberg.

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