62 PEARLS [CH. 



apatite: in Mohr's scale, this occupies the position 

 indicated in the following : 



Apatite 5, Orthoclase 6, Quartz 7, 

 Topaz 8, Diamond 10, 

 and the pearl is therefore easily scratched by many 

 other stones. The specific gravity of oriental pearls 

 varies, but the average may be taken as being from 

 2'650 to 2'686. The specific gravity of fresh-water 

 pearls seems to be higher, /.c. 2724. Poor pearls 

 are not nearly so heavy and the specific gravity may 

 be much less — averaging 15 in fact. 



In addition to the smaller spherical true pearls, 

 there occur irregularly rounded bodies, often of very 

 considerable size, known as baroque or baroche 

 pearls. These are sometimes mounted in jewellery 

 so as to hide their irregularity, but many have been 

 used so that their very irregularity added to their 

 value. At the beginning of the 18th century' there 

 was quite a popular craze for baroche figures. 

 Curious, quaint men and animal figures were con- 

 structed with the aid of the pearls and precious 

 metals. Many of these are to be seen in the British 

 Museum. There are good collections, too, in the 

 Louvre and in the Dresden ^Museum. 



At the present time small baroche pearls are 

 being mounted in necklets and bracelets. 



The colour of pearls varies very considerably, and 

 all the possible shades between pure white and black 



