106 THE WEALTH OF THE SEA 



ing approximately as the square of the weight. Usu- 

 ally, in estimating the value of a pearl, a base value 

 for a gem weighing one grain (fifty milligrams) is 

 established, and this figure is multiplied by the 

 square of the number of grains that the pearl 

 weighs. For example, if a one-grain pearl is valued 

 at ten dollars (called the base price), then a three- 

 grain pearl of the same quality would be worth ninety 

 dollars (3^ X 10 = 90). As a rule marine pearls are 

 of greater value than those from fresh-water mussels, 

 other considerations being equal. Spherical pearls 

 with imperfections in one spot are worth nearly as 

 much as perfect pearls, for the defects can be hidden 

 by setting. 



Seed pearls are those which weigh less than a 

 quarter of a grain each. These small pearls are of 

 relatively little value and are often sold in bulk. 

 Baroque pearls are those which do not have any 

 typical form, and usually they are of relatively little 

 value unless the form is that of a flower or animal, 

 in which case they are prized as curiosities. 



Utilization of Pearls and Mother-of-Peakl 



Pearls are either utilized for necklaces or are 

 mounted on pegs or rings or on studs. Strung pearls 

 may also be made into collars. 



When pearls are taken from the shells they require 

 no polishing or other preparation as do precious 

 stones. If they are to be strung, they must be drilled. 

 Formerly this was accomplished by means of a bow- 

 drill operated by hand. This operation is so slow 

 and tedious that one man can drill not more than 



