the world > animals > invertebrates > subkingdom Metazoa > grade Triploblastica or Coelomata > class Pelecypoda or Conchifera > [noun] > bivalves > that produces pearls > pearl (3)
pearlc1375
A hard, smooth, usually round, iridescent mass, typically white or bluish grey, formed of layers of calcium carbonate deposited around a foreign…