Cameo-Cutting

CAMEO-CUTTING The black helmet is one of the best shells for cameo-cutting. It has an "onyx ground," a dark coat under the pile outer layer, so that the figure will stand out well. The inner lip of a large shell should yield several brooches. Usually the back• ground is claret-coloured, instead of black.

The bull's mouth is red under a white outer coating. This is known as a "sardonyx ground." C. cornuta cuts a white figure on an orange ground. The queen conch (Strombus gigas) is pink over a white ground.

138 The Helmet Shells. Cameo Shells The two semi-precious stones named in the descriptions of cameo shells call attention to the fact that cameo-cutting, one of the fine arts of antiquity, used stone only as material, for centuries. Then lava came to be used for cheap work. Shells were first used in 182o in Italy. The best shell cameos are made

in Genoa and Rome. Many cutters are at work in Paris.

C. cornuta has the fault of "doubling" occasionally: that is, its two layers separate, and the work counts for naught. The pink queen conch has the fault of fading. At best, it furnishes but one good brooch.

The red underlying the white in C. rufa becomes thinner and paler as it extends backward, so a single brooch and a few cuff buttons or shirt studs are all a big shell can be expected to yield. Still, the enamel is so thick and the colours so good, this species will always remain in great request for cameos. There are often twenty lamina' or layers of enamel on the lip. Besides cameos, beads are cut from the linings of helmet shells.

139