600 APPENDIX 



shall resemble genuine pearls as closely as may be. With the consideration of this subject 

 we shall close. 



IMITATION PEARLS — One of the best imitations of a pearl is furnished by a 

 polished sphere of mother-of-pearl, but it differs very essentially from a natural pearl 

 inasmuch as the coats of which it is built up are not concentric. In 1680, or possibly even 

 earlier, in 1656, Jacquin, the Parisian rosary maker, discovered a means whereby imitation 

 pearls, which reproduce the beautiful pearly lustre of genuine pearls, may be manufactured. 

 His method is still employed, and on it depends a flourishing industry. The first step is 

 the production of hollow, thin-walled glass beads of " girasol," a colourless, easily fusible 

 glass manufactured for the express purpose. In form these may be spherical, ovoid, or 

 pear-shaped, or they may be made to resemble baroque pearls. The inner surface of these 

 beads is then coated with a silvery-white material obtained from the scales of certain fishes, 

 for example, from the white-fish and the bleak {Albui'iius lucidus). This material lies just 

 beneath the scales, from which it is separated by shaking the same with water. The 

 microscope reveals the fact that it consists of numberless minute, irregular, rhombic plates. 

 One pound of the substance is yielded by seven pounds of fish scales, to provide which from 

 18,000 to 20,000 fishes are necessary. This silvery-white material, when mixed with a 

 solution of isinglass, yields a thin, glutinous pulp, known in the trade as " essence d'Orient." 

 It is introduced into the hollow glass balls, over the inner surface oi which it is spread 

 uniformly. When dry, this inner coating of silvery-white material gives the beads ver}^ 

 much the appearance of real pearls, so that even an expert may be deceived at the first 

 glance. In order to make them more substantial, the beads are filled with wax. When 

 carefully made, they resemble very closely good Indian pearls, and are much worn in place 

 of these, although on account of the care necessary in their manufacture thev are not at all 

 cheap. Less carefully made beads are employed in the cheaper articles of je^^'ellery, and 

 though they imitate real pearls less perfectly, yet the beautiful pearly lustre is always 

 reproduced with more or less fidelity. 



Very beautiful artificial pearls, with a lustre like satin, are sometimes made from the 

 incisors of the Dugong, a whale-like, aquatic mammal belonging to the group which 

 includes sea-cows. It inhabits the sea in the neighbourhood of the Dahalak Island, which 

 lies in the Red Sea off Massaua, already mentioned as a pearl-fishing station. Imitation 

 pearls of this kind are not, however, frequently met with. 



In recent times the so-called opaline glass has been used for the manufacture of imita- 

 tion pearls, the resemblance to real pearls being given by a careful treatment with hydro- 

 fluoric acid. 



Black pearls can be imitated very successfully in haematite, as we have already seen 

 under this mineral. A polished ball of hasmatite often resembles a black pearl very closely, 

 especially when not too highly polished. It is readily distinguished, however, by its high 

 specific gi-avity and by the fact that it feels cold to the touch. Red spheres cut from the 

 shell of the great West Indian univalve mollusc, Strombus gigas, have a lustre which is 

 somewhat peai'1-like, but they are moi'e easily passed off' as coral than as pearls. 



