A crab that lives inside an oyster and Quahog Pearls

Pinnotheres a.ka. Pea Crab lives inside oysters. It has a very soft shell and hence seeks protection by living inside an oyster. Priya Raju stumbled on this when she was looking for quahog pearls which is another rare product of nature – a pearl made by clams. It has been making waves for the price it fetches in the market. Queen Elizabeth is supposed to have an ornament with a purple quahog pearl in it.  

 Excerpt from http://www.preciousgemstones.com/gfsummer05.html

The quahog pearl is not technically a pearl since it does not come from an oyster. The quahog is a thick-shelled member of the clam family and are simply called “hard clams” or “hard-shell clams.”

(Via Priya Raju)