A cultured pearl is an organic gemstone created in a controlled environment, such as a pearl farm, using a bivalve mollusk. The centre of a pearl is referred to as “nucleus”. The nucleus is a mother of pearl bead derived from the shell of a pearl-bearing mollusk. The nucleus must be implanted with a tissue graft from a donor mollusk into the gonad or existing pearl sac of the mollusk. As a defence mechanism, the mollusk secretes nacre, a composition of calcium carbonate and conchiolin. The nacre forms in concentric layers around the nucleus.
There are pearls that are nucleated with only the living tissue of another mollusk and no bead. These pearls are referred to as “non-” or “tissue-nucleated”, but are still considered cultured. Though they have no bead centre, they are technically nucleated with tissue which has been purposefully placed by a human hand, into a mollusk in captivity. As there is no central, spherical form around which the pearl nacre will grow, non- or tissue-nucleated pearls tend to be very baroque in shape and are rarely found in round shapes.
A pearl can not form from a grain of sand as nacre does not bond with inorganic materials.
Though produced with some human intervention, pearls are fundamentally a natural, organic material. Pearls are created through a natural growth process that, in the context of pearl culturing, is enhanced, but not in any useful way controlled by human intervention. There is simply no such thing as a “perfect match” whether in colour, shape, lustre etc. This is the one trait, unique to organic gems, that sets them apart from coloured stones and diamonds. Whilst the most costly pearl strands are those that display very little difference between beads, these strands often take years to assemble and are priced accordingly.
Slight variations in colours, lustre and shapes of pearls, even within a single strand, are to be celebrated and enjoyed. If true uniformity is what you crave, you simply will not find it in organic gems such as pearls.
Dyed pearls are cultured, generally freshwater pearls that, as a result of their shape, size or other “imperfect” traits, have been set aside for enhancement. These are pearls that, two decades ago would have been discarded, never to be used for jewellery purposes. Recently, however, such pearls are being dyed a range of “natural” colours (pinks; golds; browns) and “exotic” colours (peacock blue; grape purple) and sold for far less than traditional white and off-white pearls. These pearls are sold at far lower price points and have brought a fresh, young energy to the pearl industry. Younger, more edgy clients who never would have worn something as staid as their mother’s strand of pearls may find that a strand of neon green, side drilled drop pearls is just the thing to complete their look. And at a fraction of the price of akoya pearls, these new pearl lovers can afford to purchase a rainbow of options.