PKOCESS OF CUTTING 79 



length so as to enable them to be used as ear-rings or to be strung on a thread with others. 

 The application of the terms briolette and pendeloque is extremely variable ; as mentioned 

 above, they are sometimes applied to the double rosette. Small stones bounded on all sides 

 by more or less regularly distributed facets, not elongated in any one direction more than 

 another, and bored so that they may be strung on a thread, are known as beads. 



5. Rounded forms. — As a general rule, only transparent stones are faceted ; 

 chalcedony and other translucent stones are occasionally cut in this way ; opaque stones, 

 like turquoise, are never faceted, but always cut en cabochon. The rounded forms with 

 convex surfaces, characteristic of this style of cutting, are shown in Plate IV., Figs. 17 to 19. 

 Many deeply coloured transparent stones, such as garnet, are often cut en cabochon, as are 

 also those stones whose beauty is due to their peculiar optical effects ; such, for instance, 

 as cat's-eye and precious opal. The flat base of these rounded forms is circular or elliptical 

 in outline, and from this rises a more or less convex dome (Fig. 17 b). Transparent stones 

 of a deep colour, for example garnet, are sometimes hollowed out at the back, the inner 

 surface having the same curvature as the outer, as is shown by the dotted line in Fig. 17 b. 

 Not only is the transparency of the stone increased by this means, but facility is given for 

 removing any faulty portions of the interior of the stone. A stone cut in this manner is 

 known as a shell, and, in the case quoted, as a garnet-shell. F'requently the flat base just 

 described is replaced by another convex surface of the same or difl^erent curvature as the 

 upper portion ; the stone has then the form of a double convex lens, as shown in side view 

 in Fig. 19 b. The form with one curved surface is known as the single cabochon, while that 

 with two is referred to as a double cabochon ; a much flattened form having only a slight 

 curvature is described as tallow-topped {goutte de suif). 



The convex dome of transparent or translucent stones cut en cabochon sometimes has a 

 border of small facets arranged in one or several series (Fig. 18 b). Not infrequently, in the 

 cheaper coloured stones and in glass imitations, the table of the brilliant-, the step-, and the 

 table-cuts is given a slight curvature. 



Bastard Jbrms are those which are not pure examples of any of the typical forms 

 desci'ibed above, but combine in themselves portions of any of these types. Rare and costly 

 gems are never so cut, but bastard forms are common enough in inferior stones and glass 

 imitations. Such stones are often cut also in quite irregular and unorthodox forms,-which 

 are not subject to any definite rule, but depend solely upon the caprice of the cutter. Of 

 such forms it is obviously neither possible nor desirable to give detailed descriptions. The 

 facets of these capricious forms are sometimes regularly and symmetrically arranged, but at 

 other times this is not the case, and the stone is then described as cap-cut. 



The form of cutting specially suited to each individual variety of precious stone will be 

 mentioned with the special description of that stone. 



B. PROCESS OP CUTTING. 



The method by which a rough stone is transformed into a faceted gem is in principle 

 very simple. That part of the surface of the rough stone at which it is desired to place a 

 facet is rubbed with a harder stone or with some other convenient substance. The harder 

 stone abrades small fragments from the softer, and the surface of the latter is gradually 

 woni away and replaced, if the operation has been suitably performed, by a plane face, the 

 so-called facet. This operation is repeated until all the facets required for the particular 

 form the stone is desired to take are produced. A rounded surface is obtained by a method 

 essentially the same as the one described. 



