Baroque Pearls - What are they?
Baroque pearls are simply pearls that are not round and have an undefined shape. Freshwater pearls are most commonly baroque as freshwater pearls are mantle-tissue nucleated instead of bead nucleated. So the pearls are almost never round. Akoya pearls (commonly known as cultured saltwater pearls) can also be baroque, but the baroque shape of an Akoya pearl differs from that of a freshwater pearl. This is because Akoya pearls are bead-nucleated and thus have a perfectly round bead within. So in the event a harvested Akoya pearl is a baroque, it has a small tail that comes to a sharp point behind a rounded front.
The most valuable of baroque pearls are the South Sea and Tahitian pearls. These pearls are produced by black-lipped oysters and white-lipped oysters). Although these are a variety of cultured saltwater pearls, the amount of time that the pearls are cultured dramatically increases the depth of the nacre, and the likelihood of producing a baroque pearl. Most Tahitian pearl farm harvests, for example, produce more than 40% baroque and semi-baroque pearls.
Mother of Pearl - What is it?
Nacre, also known as "mother of pearl" is a naturally occuring organic-inorganic composite. It is formed of layers of calcium carbonate in the form of aragonite and conchiolin (a scleroprotein), separated by elastic (such as chitin and lustrin). This mixture of hard and elastic domains makes the material strong yet resilient.
The iridescent inner layer is considered highly attractive by many cultures and is often used in making jewelery or as inlays in wood furniture and guitars.
When a mollusk is invaded by a parasite or is irritated by a foreign object that the animal cannot eject, a process known as encystation entombs the offending entity in successive, concentric layers of nacre. This process eventually forms what we call pealrs and continues for as long as the mollusk lives.
Other guides relating to jewelry and gemstone buying which you may find helpful are as follows: