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Sec. I, Ch. 4: Working of Precious Stones

Sec. I, Ch. 4: Working of Precious Stones Page of 366 Sec. I, Ch. 4: Working of Precious Stones Text size:minus plus Restore normal size   Mail page  Print this page
The Working of Precious Stones.                29
and most of the Semi-Precious Stones. It is said to be the crowning invention in the art of diamond-cutting. It was due originally to Vincenzio Peruzzi, of Venice ; a city which was, in his time, the chief seat of the Diamond trade.
As a Brilliant, the Diamond has almost the form of two cones united by their bases ; the upper one being so truncated as to give a large plane surface at the top, while the lower one is much less truncated, and in fact, terminates almost in a point The stone being set with the broad plane uppermost, produces the effect of great depth of light, and its many facets increase what is termed its play of light ; the density of the material naturally intensifying the refractive power, and thereby increasing its brilliancy. The plane surface at the top is called the table ; the bottom plane is called the culet or culette; the junction of the upper truncated pyramid with the lower is the girdle ; and the lower pointed portion the pavilion, Between the table and the girdle are generally thirty-two facets, and below the girdle twenty-four. These facets receive their names from their forms. Star facets are those whose edges abut on the table ; the others are generally triangular. Accord­ing to the number of facets, the Brilliant is said to be single, double, or Old English cut. The Brilliant depends greatly upon the facetting for its exceeding beauty.
The English make the girdle rather sharp ; while the Dutch make it broader. The former method brings out the play of light better.
A form, called the " Star " was invented by M. Caire, to take advantage of the clear portions of rough Diamonds, which could not be otherwise used without great sacrifice of material. The Star-cut Diamond, as it is now worn, must be cut with extreme exactitude, avoiding the very slightest irregularity.
Sec. I, Ch. 4: Working of Precious Stones Page of 366 Sec. I, Ch. 4: Working of Precious Stones
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