Pearl

This small, nearly round pearl, measuring 6.5 millimetres in diameter, formed naturally along the inner edge of an oyster shell during the animal’s effort to expel an irritant. The pearl remains welded to the edge of the  Pinctada radiata shell. This type of shell occurs throughout the Indo-Pacific and Mediterranean regions.

This pearl on shell is a rare example of a nacreous (mother-of-pearl) specimen from Madagascar. It was fished at the end of the 19th century.