Baroque

Baroque pearls are strictly all non-round pearls but the term is usually applied to pearls which are not round but which nevertheless have a good rounded surface all over. Freshwater pearls are most commonly baroque as freshwater pearls are mantle-tissue nucleated instead of bead nucleated. So round pearls are the exception, although more are being produced as techniques improve. The most valuable baroque pearls are South Sea and Tahitian pearls which are produced by Blacklipped and White-lipped oysters (Pinctada margaritifera, and the Pinctada maxima).

Baroque white freshwater pearl necklace

Commercial baroque pearls tend to be bigger pearls – there is a balancing act for the pearl farmer between leaving the pearl in the mollusc with the chance of a big round pearl and the likelihood that the pearl will go out of round and become baroque and therefore less valuable – but for the buyer, you will be getting a lot of nacre for your money.

Bead Nucleation

There are two basic types of farmed pearls: bead nucleated and tissue nucleated. (The other main type classification is between cultured or farmed and natural or wild pearls)

Nucleation is the process which starts off the growth of a cultured or farmed pearl. It involves inserting something into a nacre-producing mollusc to trigger production of a pearl. This nucleus can be either just a tiny sliver of mantle tissue on its own or a sliver of mantle tissue plus a bead or other shaped foundation. In either case a nacre secreting pearl sac grows and a pearl is made within that sac.

Bead nucleated pearls include all Tahitian and south sea pearls, akoya pearls and many modern big freshwater pearls (brands Edison and Ming – see separate entry under Edison)) as well as fancy shapes such as coins or hearts.

Tissue nucleated pearls are mostly all freshwater pearls which are therefore all nacre, solid pearl. no bead inside. (Chinese and Biwa freshwater pearls)

Keishi pearls are an exception. They are the pearls formed inside a usually pre-existing pearl sac from which a pearl has been removed (think of how a balloon looks when the air seeps out over time and you get the idea of a keishi pearl.

Mantle tissue is used because that is the area of tissue which specifically secretes nacre. It’s usually there to make the mollusc’s shell but will produce nacre wherever it is – a talent utilised by the pearl farmer.

Placement of the nucleus varies as well. Beads are placed in the sex organ – the gonad – of the mollusc and only one per mollusc. (You might think that this would stop the mollusc from wanting to reproduce but there is some research which indicates it make them more not less active!)

Tissue nucleated pearl grafts can be many to a mollusc and are placed in the mantle.

All sea pearls are grown around a bead. It used to be that beads were not used in the production of most freshwater pearls (exceptions include coin pearls for example) However the last couple of years have seen the development of bead nucleation in freshwater pearls, producing second or third graft round pearls of stunning colour, lustre and shape. High quality bead ‘nuked’ pearls are still exceptional and unusual and therefore very expensive, but can be up to 18mm.

Biwa

Or sometimes biwi-

A freshwater pearl grown in lake Biwi in Japan. Biwa pearl production stopped some years ago in the lake due to pollution but some farmers are having some success with growing these rare pearls again

Stick pearls are often generically mis-described as biwa pearls. They aren’t.

Bleaching

White pearls are colour treated by bleaching. This applies to both akoya and freshwater pearls. Sometimes after bleaching a faint pink overtone is added as this can make the pearl more attractive

Black-lipped Oyster

Pinctada margaritifera This oyster produces the Tahitian black pearl, which is neither black, nor comes from Tahiti.

Blinking

Term to describe poor quality bead nucleated pearls where the nacre does not even fully cover the nucleus. When the strand is rolled the pearls look as if they are blinking. Beware of akoya pearls which are cheap. They will almost certainly have very thin nacre which will wear through.

Blister

A pearl that is attached to the inner surface of a mollusc shell.

baroq

Often rounded on one side and flat on the other. Sometimes also called a fastener pearl . Most often used to make stud earrings, because in larger sizes round pearls can be too proud of the earlobe.