Wished at Paris so early as 1407 ; and also of three diamant slypers at
Bruges, in 1465. But the very title of the last professionals proves of
itself that their practice extended no further than the polishing the
natural faces of the crystal, or the removing the greenish film that
frequently veils its purity ; operations to be effected with the aid
of emery alone, although by a very tedious process.*
Louis
de Berghem first essayed his new-invented art upon three large Diamonds
entrusted to him by Charles the Bold ; the first a deep-shaped stone
(confounded by all retailers of the story in later times with the famous Sancy) ; the second flat and thin, a table in
fact, which the Duke presented to Sixtus IV. ; the third, being very
irregular in outline, the artist cut into the figure of a heart and
triangle combined, which was set in a ring shaped as two hands clasped
(the symbol of good faith) and sent to Louis XI.; an allusion, though
in an acceptable form, to his deficiency in that virtue. The
improvement in the beauty of the Diamond, thus treated, was so
remarkable that Charles rewarded the inventor (according to the
testimony of his descendant Robert de Berquem) with the munificent
donation of 3000 ducats.
The
exact style of cutting Diamonds thus inaugurated may still be seen in
numerous jewels dating from the next century. The only patterns known
to Kentmann, writing in 1562, are the Demant-punkt and the Demant-tafel. The first, the Point (a
name still in use), is a four-sided pyramid, produced by simply
polishing the faces of the native octahedron, and making them exactly
true and regular. The other, the Table, required much more work; the apex of the crystal being ground down to a square, or oblong,
