FORMS OF CUTriNG 75 



also noticeable from the fact that the facets, instead of being in multiples of four, are in 

 multiples of three. 



The forms just described may be regarded as typical brilliant forms, and are used far 

 more frequently than any other. They are nevertheless subject to certain modifications, 

 not, however, deviating far from the normal types. These modifications usually take the 

 form of variations in the arrangement and number of the facets ; in the latter case further 

 small facets are introduced in groups, which are placed symmetrically relative to the other 

 facets. The majority of the large historical diamonds are cut in the brilliant form, as an 

 examination of Plates X. and XI. will show. On comparing these forms with the normal 

 forms of Plate II. a strong general resemblance, accompanied by differences in minor details, 

 will be noticed. 



To bring out all the beauties of a stone, and to display them to the greatest possible 

 advantage, involves infinite care and precision in the cutting. The facets must be regularly 

 and symmetrically grouped, and corresponding facets must be of precisely the same size ; 

 moreover, it is of the greatest importance that all the different parts of the stone should be 

 correctly proportioned. In this connection may be mentioned the following rules which 

 are generally observed, and which are only departed from where there are special reasons for 

 so doing : 



The height of the upper {)ortion of the brilliant above the girdle must be one-third, 

 and that of the lower portion must be two-thirds, of the total thickness of the stone from 

 table to culet. The diameters of the table and culet must be respectively five-ninths and 

 one-ninth of the diameter of the girdle ; hence the diameter of the table is five times that 

 of the culet. Few of the best cut and most beautiful brilliants show any essential deviation 

 from these dimensions ; the exceptional cases mentioned above occur when the rough stone 

 is of such a shape that to give it these proportions would involve too great a waste of 

 material ; or, again, in the case of a coloured stone, where the thickness is varied in order to 

 obtain the particular depth of colour desired. 



The " Koh-i-noor," the famous diamond now in the English crown jewels (Plate X., 

 Fig. 5), on account of the former reason departs considerably from the typical form. The 

 " Regent," a large brilliant in the French crown jewels, is perhaps the most perfectly 

 beautiful stone of its kind existing at the present day (Plate XL, Fig. 8). It conforms 

 with the greatest precision to the proportions laid down above, and consequently far 

 surpasses the " Koh-i-noor " in brilliancy and play of colours, although the two stones are 

 equal in quality. 



It remains to be mentioned that the girdle of a brilliant is sometimes left with sharp 

 edges (Plate X., Fig. 5), as is the custom of English gem-cutters ; or the edges may be ground 

 down (Plate XI., Figs. 8 and 9), as is done in Holland. The former plan improves the appear- 

 ance and effect of the stone, but the sharp edges are liable to get chipped, which is not the 

 case when they have been rounded off. 



Mention may be made here of the half-brilliant (or brillonette), which is very 

 occasionally made use of. It is essentially an ordinary brilliant, the under portion of which 

 is replaced by a single large face, which forms a base to the upper portion as in rosettes. 

 This device is occasionally resorted to when the rough stone is very flat, but the appearance 

 of a stone so cut is far inferior to that of a complete brilliant. 



The star-cut-, which is closely related to the brilliant form, was devised by the Parisian 

 jeweller, Caire, at the beginning of the nineteenth century, and is illustrated in Plate III., 

 Fig. 1 a, b, c. In this form Caire aimed at combining the advantages of the brilliant with 

 those of the rosette. As may be seen from the diagrams, the facets are arranged in 



