172 PEARLS AND PEARLING 



wider and deeper and the erosion is reduced so the shells 

 are much smaller. 



An investigation of some of the ocean pearl fisheries 

 also furnishes some information relating to the color of 

 pearls. 



The pearls from the Ceylon fishery in the Gulf of 

 Manaar, off the east coast of the island, are of a rather 

 uniform creamy yellow color. The sea-coast there is 

 even with a low-land plain back of it. The only moun- 

 tains are in the extreme southern part of the island, 

 where plumbago and precious stones are found. 



In the pearl fisheries of Lower California, where the 

 most approved diving outfits are used, pearls are found 

 in white, pink, blue, green, brown and black colors. The 

 adjacent land is mountainous, while the mining* region 

 comprises eighty per cent, of the area of Mexico. The 

 minerals found there are gold, silver, lead, copper, plati- 

 num, iron, mercury, tin and zinc. 



The pearl fisheries of Costa Rica, Panama and Co- 

 lombia are famous for their black, blue, pink and green 

 tinted pearls. These countries are rich in minerals and 

 produce gold, silver, iron, copper, lead, platinum, mer- 

 cury and zinc. These circumstances seem to indicate that 

 local mineral deposits also have something to do with the 

 colors of the ocean pearls. 



