BORING— ENGRAVING 85 



of stone, to the exclusion of others. In diamond-cuttmg works diamonds only are cut, 

 while the work of other establishments is limited to the treatment of other precious and semi- 

 precious stones to the exclusion of diamonds; such establishments are known as precious-stone 

 or fine-stone-cutting works. Another branch of the industry is concerned exclusively with 

 the large ornamental stones with plane surfaces, or only a small number of facets, such as 

 are suitable for use as stones for signet-rings, crosses, and so forth : here the less valuable 

 stones only are used, such as agate, chalcedony, jasper, &c. In addition to the objects just 

 mentioned, articles such as letter-weights, cups, vases, boxes, etuis, inkstands, stick and 

 umbrella knobs and handles, knife-handles, &c., are fashioned at these large-stone-cutting 

 works, and such materials as granite, marble, serpentine, &c., which do not fall under the 

 head of precious stones, are made use of in the industry beside the minerals mentioned 

 above. The work carried on respectively at the large- and the small-stone-cutting establish- 

 ments is now to a large extent regarded as different branches of the same trade, and is often 

 directed by the same firm, but the diamond-cutting industry is a distinct and specialised 

 calling, which is never combined with other branches of the trade. 



C. BORING. 



Not infrequently precious stones, such as garnets, are strung together and worn as 

 beads, which necessitates that they shall be pierced. In the cases in which precious stones 

 have a technical application, such, for instance, as the making of pivot-supports for watches, 

 and the orifices through which very fine gold and silver wires are drawn, it is often necessary 

 to bore a hole through the centre of the stone. The boring is usually effected by the rapid 

 i-otation of a fine diamond point, fixed in a metal holder, which acts like a drill. The 

 diamond point of the drill is often replaced by a steel point charged with diamond powder 

 moistened with oil. For convenience in conducting this operation, special machines are 

 constructed by means of which hard stones are bored with ease and rapidity. 



D. WORKING ON THE LATHE. 



Many stones, especially the softer ones, occurring in large masses, furnish material for the 

 manufacture of balls and other rounded objects. Such articles may be turned on the lathe ; 

 this machine is more appropriate for the class of work carried on in the large-stone-cutting 

 works, and is seldom used in the working of precious stones. Nevertheless the hardest 

 stones used for gems may be worked in this way, the steel turning-tool being replaced by a 

 diamond point ; as, however, the turning of precious stones is but rarely undertaken, it 

 need not be furthei* considered here. 



E. ENGRA.VING. 



Precious stones are not only cut in various forms, but they are also engraved with 

 devices such as figures, crests, monograms, or with inscriptions. In the cutting of a stone, 

 the lapidary strives to give it such a form as will best display its natural beauty ; this 

 beauty depends essentially on the characters of the stone, not on the form given it by the 

 lapidary ; this form being simply a means to an end, namely to develop to the uttermost 

 the natural beauties of the stone. The engraver, on the other hand, aims at producing a 

 work of art of value in itself; the material upon which the artist works is a secondary con- 

 sideration, for he will probably be able to produce just as fine an engraving on some other 

 stone of an entirely different character. 



The art of engraving and cutting precious stones is very ancient, much older indeed 



