DIAMOND: APPLICATION IN JEWELLERY 241 



is the position reversed and the so-called Indian setting adopted. The dazzling appearance 

 of the brilliant is due to the way in which the rays of light entering the stone are reflected 

 from the facets at the back, pass out by the front facets and reach the eye of the observer 

 in the manner already described. As compared with a brilliant, other diamonds appear 

 dull and lifeless, for the arrangement of their facets does not admit of the passage of light 

 rays in such a way as to'produce the most favourable effect, either as to brilliancy or play 

 of colours. It is essential, however, in order to produce the greatest effect, that even the 

 brilliant form should conform rigidly to the rules of proportion which have been already 

 laid down. The " Regent," for example, the proportions of which are strictly accurate, is a 

 far more dazzling and brilliant stone than is the " Koh-i-noor," which is cut with too small 

 a depth. 



The brilliancy and fire of a cut diamond is enhanced by suitable illumination; the 

 source of light should not be too large, otherwise the separation of the differently coloured 

 refracted rays is masked, and the light reflected appears to be white ; neither should the 

 source of light be surrounded by an opal shade. A brilliant appears at its best when 

 illuminated by a number of small flames ; and the eft'ect can be still further increased by 

 attaching the stone in its setting to a thin metal rod or wire, when the quivering motion 

 imparted to the stone by every movement produces rapidly changing flashes of colour. 



Although each of the different forms of cutting which have been described may under 

 various circumstances be made use of for the diamond, yet there are but two forms in 

 general use, the first and most important being the brilliant, the other, the rose or rosette. 

 The diamond is the only gem which is so invariably cut in these forms, and hence is often 

 loosely referred to as a brilliant or a rosette. 



Whenever the form of a rough stone permits, it is always cut as a brilliant, no matter 

 what its size may be. Plate IX. shows in actual size a series of diamonds cut in the 

 brilliant form, viewed from above, and ranging in weight from ^ to 100 carats ; from a 

 study of this series some idea of the actual sizes of stones of different weights may be 

 gained. As a rule only small diamonds of little thickness, fragments cleaved off in the 

 fashioning of a brilliant from a large stone, and large diamonds which have not sufficient 

 depth to be cut as brilliants, are cut as rosettes. Sometimes, by preference, a large thin 

 stone is made into several small brilliants and not into a single large rosette. 



^ 10 



25 



50 Carats. 



Fig. 4i. Actual sizes of rose diamonds of 1 to 50 carats. 



As in Plate IX., a series of brilliants in actual size is shown, so Fig. 44 shows the 

 actual sizes of a series of rose diamonds ranging in weight from 1 to 50 carats. Stones of 

 surprisingly small size are often to be met with cut as roses, with regularly arranged facets ; 

 they may be so small that 1500 or even more weigh no more than a carat. Stones of 

 very small size are not generally cut as brilliants. Small roses, of which 100 or 160 are 

 required to make up the weight of a carat, are known as piece-roses ; the Dutch lapidaries 

 are specially skilled in the art of cutting extremely small stones. Very minute splinters of 

 diamond are often furnished with a few irregular facets, when they are known as senaille, 



a 



