<P> Before the beginning of the 20th century , the only means of obtaining pearls was by manually gathering very large numbers of pearl oysters or mussels from the ocean floor or lake or river bottom . The bivalves were then brought to the surface , opened , and the tissues searched . More than a ton were searched in order to find at least 3 - 4 quality pearls . </P>
<P> Before the beginning of the 20th century , the only means of obtaining pearls was by manually gathering very large numbers of pearl oysters or mussels from the ocean floor or lake or river bottom . The bivalves were then brought to the surface , opened , and the tissues searched . More than a ton were searched in order to find at least 3 - 4 quality pearls . </P>
what type of oysters have pearls in them
what type of oysters have pearls in them
pearl oysters
pearl oysters