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Natural (or wild) pearls, formed without human intervention, are very rare. Many hundreds of pearl oysters or mussels must be gathered and opened, and thus killed, to find even one wild pearl; for many centuries, this was the only way pearls were obtained, and why pearls fetched such extraordinary prices in the past.
The many different types, colours and shapes of pearls depend on the natural pigment of the nacre, and the shape of the original irritant. Pearl farmers can culture a pearl by placing a nucleus, usually a piece of polished mussel shell, inside the oyster. In three to seven years, the oyster can produce a perfect pearl.
Nacre (/ ˈ n eɪ k ər / NAY-kər, also / ˈ n æ k r ə / NAK-rə), [1] also known as mother-of-pearl, is an organic–inorganic composite material produced by some molluscs as an inner shell layer. It is also the material of which pearls are composed. It is strong, resilient, and iridescent.
The flukes have a complex life cycle with freshwater snails as intermediate hosts; people swimming or washing in the water are at risk of infection. [52] Molluscs can also carry angiostrongyliasis , a disease caused by the worms of the Angiostrongylus spp., which can occur after voluntarily or inadvertently consuming raw snails, slugs, other ...
The mollusc (or mollusk [a]) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled molluscs live in the sea; many live on the land and in freshwater.
The freshwater pearl mussel (Margaritifera margaritifera) is an endangered species of freshwater mussel, an aquatic bivalve mollusc in the family Margaritiferidae.. Although the name "freshwater pearl mussel" is often used for this species, other freshwater mussel species (e.g. Margaritifera auricularia) can also create pearls and some can also be used as a source of mother of pearl.
The original Japanese cultured pearls, known as akoya pearls, are produced by a species of small pearl oyster, Pinctada fucata, which is no bigger than 6 to 8 cm in size, hence akoya pearls larger than 10 mm in diameter are extremely rare and highly priced. Today, a hybrid mollusk is used in both Japan and China in the production of akoya pearls.
Living abalone in tank showing epipodium and tentacles, anterior end to the right. Abalone (/ ˈ æ b ə l oʊ n i / ⓘ or / ˌ æ b ə ˈ l oʊ n i /; via Spanish abulón, from Rumsen aulón) is a common name for any small to very large marine gastropod mollusc in the family Haliotidae, which once contained six genera but now contains only one genus, Haliotis. [1]