PRODUCTS FROM THE SEA 351 



Artificial Pearls 



Singularly enough, artificial pearls depend for their 

 manufacture upon a marine product. About the middle 

 of the seventeenth century, a French rosary maker called 

 Jaquin discovered that fine flakes of a lustrous, pearl-like 

 substance could be obtained from small fresh-water fish. 

 He prepared a thick suspension of this and, by coating 

 alabaster or wax beads with it, succeeded in producing 

 extremely good imitation pearls, and, incidentally, laid 

 the foundations of the modern artificial pearl industry. 



The pearly substance, or " essence d'Orient " as it is 

 called by the French, is really guanin, a waste product 

 like urea, which is found in many fish, though only in a 

 few is it suitable for manufacturing purposes. Usually it 

 is present as a dull powder but for the preparation of pearl 

 essence it needs to be crystalline because only in that form 

 is it lustrous, the minute blade-like crystals reflecting light 

 and breaking it up into the colours of the rainbow. The 

 silvery appearance of the under side of many fish is due 

 to the presence of crystalline guanin in the skin. 



On the Continent the little fresh-water "ablette " is the 

 main source of pearl essence, in this country the herring, 

 and in America the sardine, herring and other fish. The 

 crystals are extracted by washing the scales and scrubbing 

 them with a mechanical stirrer, the sediment being finely 

 separated in centrifuges which throw the solid matter to 

 the sides and leave the water in the middle. Two types of 

 " pearls " are made, one from hollow and the other from 

 solid glass beads. The former are coated on the inside 

 with pearl essence and gelatine, the bead being revolved 

 rapidly until a uniform coating is obtained when the cavity 

 is filled in with wax. The more durable solid beads which 

 are made of opaque glass, are given six or more coats of 



