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Adamas, Diamond

Adamas, Diamond Page of 453 Adamas, Diamond Text size:minus plus Restore normal size   Mail page  Print this page
DIAMOND-CUTTING.
45
alone appear, as for instance in certain jewels made by her order for the Duke of Marlborough, as I have been informed on the best authority. It is the opinion of the same most competent judge that the latest and most perfect of all—the brilliant pattern —was invented some time in the reign of George I. In this the Diamond is made to assume the form of two cones united by their bases; the upper cone so much truncated as to present to the eye a considerable plane surface ; the lower but slightly so, terminating almost in a point. Thus the stone, being set with the broader plane upmost, possesses great relative depth, which, strengthening its refractive power, aided also by the numerous facets that cover the sides, both combined mightily augment the brilliancy of the Diamond (whence the name) by confining the rays of light inside it.
In the technical description of the brilliant (" brillant re-coupe "), the upper surface is the table ; the junction of the upper truncated pyramid with the lower, or the broadest part, the girdle; the lower pointed portion, the collet (" culasse"). Be­tween the table and the girdle are 32 facets; below the girdle 24. Facets are named from their forms, " dentelles, losanges, feuil-lets." As a rule, small stones lose 38 or 40 per cent, of their weight, large ones 50 and even more, in being reduced to this form; but in the old perfect Indian octahedrons the loss was much less, the crystal naturally lending itself to the shape.
At that period the chief seat of the business of diamond-cut­ting for the world was London; and even now an old town cut brilliant can immediately be distinguished from those prepared by the modern Dutch (who sacrifice beauty of form to preserva­tion of weight), by the superior accuracy and excellence of the work, and consequently it commands a far higher price in the market; for the lustre of a brilliant depends in great measure upon the judicious distribution and accurate finish of the facets composing its sides.
De Boot, who, assisting his imperial master/ worked long and
Adamas, Diamond Page of 453 Adamas, Diamond
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