PEARL 



Pearl is not a mineral in the strict 

 sense of the wbrd, but has long been 

 associated with gems in thought and use. 



Like amber, jet and coral, Pearls are a 

 product of organic or living forces, not of 

 inorganic nature. Mollusks, chiefly of 

 the order of bivalves, are the organisms 

 which produce Pearls. They are a 

 product, however, not of health and nor- 

 mal life, but of disease and abnormal 

 conditions. This is well known by the 

 Pearl fishers, so that, in searc'hing for 

 Pearls, they pass by the young, well- 

 formed mollusks, to gather only those 

 appearing old, diseased and distorted. 

 The formation of Pearls by a mollusk 

 is generally the result of some persistent 

 irritation of the mantle. The agent of 

 irritation may be a grain of sand, a liit 

 of seaweed, an infusorian, a parasite or 

 an egg of the mollusk itself. In other 

 cases the agent of irritation is not 

 known, as many Pearls show no change 

 of composition at the' center on being cut 

 open. Ordinarily, however, the origin of 

 the Pearl seems to be an effort on the 

 part of the mollusk to protect itself from 

 such an irritant as one of those above 

 mentioned by secreting over it a calcare- 

 ous deposit similar to that of which it 

 forms its shell. This deposit will have 

 tlie color and character of the interior of 

 the shell or, if the color of the shell 

 varies in different portions, that of the 

 part of the shell which is nearest. Un- 

 less the interior of the shell possesses 

 the peculiar nacreous luster desired in 

 Pearls, these will be of no value. 



The form and size of the Pearls pro- 

 duced by mollusks varies considerably. 

 Only those which are perfectly spherical 

 or drop-shaped are considered of first 

 quality for jewelry, but these are only a 

 small part of the forms produced. Ir- 

 i-egular protuberances or convexities of- 

 ten distort the spherical form and highly 

 complex and grotesque shapes occur. 

 One such Pearl is known having a re- 

 markable resemblance to a bust of Mi- 

 chael Angelo. Others resemble insects 

 or fruits. These resemblances can be 

 enhanced by proper mounting and the 

 addition of a little gold and enamel. 



Some fanciful work of this kind has 

 been done and a large collection of such 

 Pearls is preserved in the Green Vaults 

 in Dresden. Such Pearls are known as 

 baroques and formerly had compara- 

 tively little value, but at the present time 

 they are being employed in tlie most 

 costly jewelry. Not infrequently the 

 Pearl becomes attached to the interior of 

 the shell as is the one shown in the ac- 

 companying plate. Such Pearls can be 

 used by cutting them away from the 

 shell, but they have much less value 

 than those well-formed on all sides. 

 Loose Pearls which form flat on one 

 side, are called button pearls, and are 

 worth only about twenty-five per cent, 

 less than round Pearls. Again, Pearls 

 may be hollow. Such are called coque 

 de pcrle, and have little value if their 

 hollow nature be known. This, how- 

 ever, is not always the case, as is shown 

 by an instance mentioned by Kunz of a 

 New York lady who had purchased a 

 Pearl apparently of good quality, except 

 for a little black spot on one side. This 

 was mounted and worn as an article of 

 jewelry until, while its owner was ap- 

 plauding at the opera one evening, the 

 Pearl broke and disclosed its interior 

 filled with a white, greasy clay. 



The Chinese take advantage of the 

 habit of mollusks to cover any intruded 

 substance with Pearl, to introduce into 

 the shells of these animals, under the 

 mantle, beads and small images. The mol- 

 lusk is returned to the water and in 

 about a year's time taken out again, 

 when the objects are found to be coated 

 with a pearly substance. Pearls so 

 formed, however, are comparatively 

 dark and lusterless and have by no 

 means the value of those of wholly nat- 

 ural origin. 



Pearls vary in size from those of mi- 

 croscopic dimensions to those as large 

 as a pigeon's egg. The latter are, of 

 course, very rare. 



The Shah of Persia is said to possess 

 the largest pearl, it being about one 

 and one-third inches in length in one di- 

 rection and one inch in another. A Pearl 

 in the Austrian crown weighs 300 car- 



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