136 MARINE PRODUCTS OF COMMERCE 



the diflFerent species of shells, it is safer to secure the thin sections directly rather 

 than to risk the operation of horizontal divisions of the thicker sections. 



The pieces of mother-of-pearl thus obtained are not entirely smooth, nor are 

 the under and upper surfaces absolutely parallel, owing to the curvature of the 

 shell. As a general rule that side of the mother-of-pearl from which the outer 

 crust has been removed is superior in color to the interior side; but, frequently 

 it is defaced by the existence of cavities. 



After the surface of the sections cut out of the shell have been freed of "bark" 

 and polished, they are formed by means of a lathe. This method resembles that 

 employed for ivory and bone. The velocity of the wheel must be carefully regu- 

 lated, for if it revolves very rapidly there is risk of splitting the mother-of-pearl; 

 to preclude the danger of overheating, the material is kept moistened with water 

 during the turning operation. 



For the more artistic inlays, as ivory or tortoise shell, it becomes necessary to 

 pierce the design on thin mother-of-pearl plaque. The design, having been ex- 

 ecuted, an imprint of it, or more often the design itself, is glued on the piece of 

 mother-of-pearl. This is now firmly set in a screw vice attached to the turning- 

 lathe and carefully cut out by fine steel saws. Here again it is essential to keep 

 the mother-of-pearl moistened, to regulate the speed of the lathe, and to apply a 

 slight coating of fine wax to the saw. For the more delicate touches the burin 

 must be used to supplement the work of the fine saw. 



At one time inlaying in mother-of-pearl was practiced to great perfection in 

 Ahmedabad, India. Examples of this work were to be seen on the wooden cano- 

 pies over the shrines of Shah Alam at Sarkhej and on stone in the marble tomb 

 of one of Sultan Ahmed's queens. The simpler designs were made by filing 

 mother-of-pearl to the required size and then inserting them into a pattern cut 

 into the block of wood. To secure more varied effects pieces of different colors 

 were worked into cement and attached to the surface which was to be ornamented. 

 The commoner sort of inlaying was still occasionally employed for the adorn- 

 ment of the frames of musical instruments. 



Cameos 



Mother-of-pearl is also extensively carved into cameos. This art is practiced 

 chiefly in Italy, where the chief center is Torre del Greco, near Naples. The shells 

 most commonly employed are of the genus Cassis, which is chiefly obtained from 

 the Caribbean Sea and Indian Ocean. 



Usually oval in outline, shell cameos are essentially bas-relief carvings in the 

 white outer layer of a conch shell, utilizing the colored inner layer as background. 

 While the classical feminine head is the most common subject, figurines or scenes 

 are more highly valued because of the greater skill required in their carving. 

 Cameos are made in standard sizes from 10 to 60 mm (measmed on the long 

 axis) to facihtate mounting as earrings, rings, bracelets, pendants, and brooches. 



Types of conch shells from which cameos may be made include the comehan, 

 sardonyx, and pink. The last two are found mainly in the Caribbean area. The 

 demand for sardonyx cameos, which have a background color varying from gray- 

 ish brown to sepia, is not now su£5cient to attract large supplies of shells; while 

 the pink shade has almost disappeared from use in the past generation, due 

 possibly to its tendency to fade. Practically all cameos made in Torre del Greco 



