The Pinna seashells are really famous for being the “silkworms” of the sea thanks to their particular ability to produce byssus, a totally natural textile material which is really fine and especially appreciated for the art of embroidery. But not everybody knows that these mussels are sometimes able to produce some pearls called Pinna pearls.
This specimen can be found in the waters of the Mediterranean Sea, Red Sea, Pacific Ocean, Indian Ocean and southern coasts of America, and it’s able to produce either pearls with nacre or pearls without the traditional layer of mother-of-pearl: the first ones are usually grey or black with bright green, blue, violet, silver and pink undertones, while the second ones are brown with orange and pink undertones.
These peculiar colors are due to the internal color of the seashell, which, during the creation of the of the pearl, hands it over to the surface of the latter, determining its particular color; usually with small dimensions, this type of pearl can be mainly found in the Adriatic Sea (with pink and reddish undertones) and in the Isles of Pines in New Caledonia (usually black).
Differently from the Margaritifera ones, which have regular and alternate layers of conchioline and carbonate of lime, these pearls have alveolar structure which presents itself with a pyramid-shaped prismatic texture that irradiates from the nucleus to the surface, a cristalline structure with conchioline walls filled with carbonate of lime. A pearl of highest rarity.