What is a natural pearl, and how are they formed? Natural pearls form when some kind of irritant, usually a small organism, makes its way into the shell of a mollusk like an oyster or a mussel.

A great irony of pearl history is that the least expensive ... To reduce irritation, the mollusk coats the intruder with the same secretion it uses for shell-building, nacre.

The Alabama pearlshell mussel, a small, endangered mollusk found in a just a few creeks in south Alabama, which can outlive ...

The oyster or mussel slowly secretes layers of aragonite and conchiolin, materials that also make up its shell. This creates a material called nacre, also known as mother-of-pearl, which encases the ...

And not every pearl comes out the same. The size of the pearl largely depends on the size of the mollusk. For example, akoya pearls can only grow about 9 or 10 millimeters in diameter, but South ...

When an irritant, typically a grain of sand, enters the mollusk, it triggers a defense mechanism. Then, the mollusk coats this irritant with layers of nacre, a crystalline substance that builds up ...

One of the most well-known attributes of these saltwater bivalve mollusks is the iridescent composite material nacre—also ...