PEARL VS MOTHER OF PEARL
Whilst people often use pearl and mother of pearl interchangeably to refer to the shiny inner layer we find in molluscs, they are actually two very distinct materials.
Both pearls and mother of pearl form from nacre, the iridescent substance made of calcium carbonate that an oyster or mollusc secretes. They're both known as organic gemstones because they're made from this same material. The distinction, however, is in where the substance takes shape.
Pearls originate inside the mollusc's body tissue, generally within the soft tissue. Once an irritant gets into the soft tissue, coating after coating of nacre takes place, which builds up a spherical pearl over time.
On the other hand, the inner covering of an oyster's shell is mother of pearl. It's the iridescent skin on the interior of most mollusk shells, which glows in a variety of hues. The lining keeps the shellfish comfortable by shielding it from irritants that might get past the shell.
Pearls have always been more valuable than mother of pearl, because it's rarer to find. Despite the fact that costs have risen in recent years, pearls remain the more valuable of the two.
To put the rarity of the two in perspective, consider that every mollusc that produces nacre will have mother of pearl in its inner shell lining, whereas only a few produce a pearl.
Pearls are typically spherical, although they may occasionally take on unusual and strange forms, as seen with keshi pearls. Typically, when jewelers work with pearls, they may go wild with the setting but not so much with the pearl itself owing to its spherical form. However, with the increase in popularity of baroque pearls, there are now more diverse pearl forms to work with.
The surface of a mother of pearl object is flat and lacks structure. It typically resembles the shell's form. As a result, mother of pearl's uses include a variety of applications that aren't utilized with pearls. The most popular usage for this material is in the decoration of a wide range of objects, such as dials, knobs, doorknobs, picture frames and other decorative items.
Both mother of pearl and pearls are organic gems. However, they differ in shape, value and composition.