The Pinctada fucata/martensii/radiata/imbricata species complex
Ever since Shohei Shirahi's book "Pearls and Pearl Oysters of the World" (1994) came out, many species that were once believed to be different have been confirmed as actually belonging to one species. Such is the case for the Pinctada imbricata species, that now encompasses species that were once considered unique to one area.
Under this name we now have the former species of "Akoya" pearl oysters: P. fucata...
P. maculata is the smallest of the Pinctada genus. The shell measures barely over 5 cm in length, and the pearls are at most 8 mm in diameter. Nacre color ranges from white to golden and brown. The "pipi" shell is used in Polynesia as a delectable source of food.
A "Pipi" shell with a natural blister in it. Notice the characteristic golden color of the inner shell.
Ecology and Habitat
P. chemnitzii is found on the Northern...
The shells of P. capensis look remarkably similar to Pteria shells. They have a longer shape that is slightly deformed. When both halves are open, the silhouette of the shell resembles a "C" shape. The luster of the inner shell is dull, making the nacre appear milky white. Sometimes a yellowish grey/bluish tint is possible. Shells can measure up to 10 cm in length.
Ecology and Habitat
P. capensis is only found on the coast...
P. albina is known as the smaller Australian Oyster. In the 1960's, studies revealed that there were local differences between the color and size of the shell. Because the differences were determined to be geographical discontinuities, the species was divided into two subspecies: P. albina albina (Lamarck) and P. a. sugillata (Reeve), which represent the western and eastern subspecies.
The species is small, only three to four...
Natural Pearls Defined
Natural pearls are calcium carbonate secretions which form within mollusks without human intervention.
Natural Pearls Accidents of Nature
Natural pearls are formed randomly and really are simple accidents of nature. When a certain type of irritant, such as a parasite, becomes lodged in the tissue of a mollusk, the animal responds by secreting a calcium carbonate substance called nacre to coat the intruder and protect the mollusk. Over a period of several years, this...