338 THE DIAMOND AND OTHER PRECIOUS STONES. 



and the Koh-i-noor, belonging; to that of England, are cut with facets 

 too large, and not sufBcientlj^ numerous. It would have been better if 

 the large ui)per surface, called the table, had been cut in a series of 

 smaller facets, made to slope toward the edge, as is done for small 

 colored stones. 



The following is my method of studying the effect of a diamond : I 

 pierce a hole in a white card a little larger than the diamond to be ex- 

 amined. Then passing a ray of sunlight or that of the electric lamp 

 through this hole, I place th(^ stone in the path of this ray, at a certain 

 distance from the hole, behind the card, so that it shall receive the light 

 on the table of its anterior surface. The rays reflected from the table, 

 and also those which pass through into the diamond, are reflected back 

 on the card, where they exhibit a white image of the table, surrounded 

 by small bands iridescent with all the prismatic colors. j!^ow, if the 

 colors are considerable in number, well separated, and equally spread 

 around the white reflection of the table, the diamond has been well cut. 

 Each of the bands indicates one of the lusters of the stone, which may 

 therefore be counted, and, consequently, in this way, the number, the 

 quality, and the symmetry of the lusters can be determined ; errors in 

 cutting can be detected ; and the form to produce the best effect can be 

 ascertained. I have always intended to undertake by this method the 

 study of the principal diamonds of France, but have always postponed 

 it, being, like Homer, too much pressed with other work. 



The second kind of cutting is called, for what reason I know not, the 

 rose. It consists in leaving a large, smooth surface underneath, and in 

 covering the upper surface with a great number of small facets, in order 

 to produce on the face, by the reflection from below, lusters and colors 

 similar to those of the brilliant. This cutting is used for stones of a 

 flat form, the weight of which would bo too much diminished in reduc 

 ing them to the form of the brilliant. In this manner the great Indian 

 diamond of England was originally cut, before it was presented to the 

 Queen ; in cutting it as a brilliant it has been reduced from ISO to about 

 103 carats. It is scarcely necessary to say that, by the process I have 

 given, the rose-cutting can be as well verified as that of the brilliant. 

 [n both, large facets should be avoided even for the larger diamonds. 

 As to the identity of the diamond known as the " Sancy," the name of 

 one of thecai)tains of Henry the Fourth, there is no agreement among 

 connoisseurs. All the diamonds which pretend to this name weigh from 

 55 to 70 carats, and are cut in the form of a flattened pear, almost 

 round, a. shape called the pendalogue, having facets above and below, 

 with a small, flat surface on the top. Several imitation diamonds cut 

 ill this style have given admirable effects, and I think that it should 

 have been adopted in the cutting of both the crown diamond of Eng- 

 land and the rough diamond, known as the ISiar of the South, presented 

 to the Academy of Sciences by M. Dufrenoy. This kind of cutting, 

 which I venture to call the Satwy^ merits as much attention as those 



