What are Pearls?
A pearl is a hard, glistening object produced within the soft tissue of a living shelled mollusk or another animal, such as snails (gastropods) clams, and scallops. Just like the shell of a mollusk, a pearl is composed of calcium carbonate in minute crystalline form, which has deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes, known as baroque pearls, can occur. The finest quality of natural pearls have been highly valued as gemstones and objects of beauty for many centuries. Because of this, pearl has become a metaphor for something rare, fine, admirable, and valuable.
The most valuable pearls occur spontaneously in the wild but are extremely rare. These wild pearls are referred to as natural pearls. Cultured or farmed pearls from pearl oysters and freshwater mussels make up the majority of those currently sold. Imitation pearls are also widely sold in inexpensive jewellery. Fully man-made using materials such as glass and synthetic substances. Imitation pearls have no intrinsic value and the quality of their iridescence is usually very poor, easily distinguished from that of genuine pearls. Pearls have been harvested and cultivated primarily for use in jewellery, but in the past were also used to adorn clothing. They have also been crushed and used in cosmetics, medicines and paint formulations.
Perhaps the best-loved gems of all time, pearls—both natural and modern cultured pearls—occur in a wide variety of natural colours. The most familiar colours are white and cream (a light yellowish brown). Black, gray, and silver are also fairly common, but the palette of pearl colours extends to every hue. The main colour, or body colour, is often modified by additional colours called overtones, which are typically pink (sometimes called rosé), green, purple, or blue. Some pearls also show the iridescent phenomenon known as orient.
Cultured pearls are popular for bead necklaces and bracelets, or mounted in solitaires, pairs, or clusters for use in earrings, rings, and pendants. Larger pearls with unusual shapes are popular with creative jewellery designers.
NATURAL PEARLS VS. CULTURED PEARLS
Natural pearls form in the body or mantle tissue of certain mollusks when epithelial cells, responsible for the secretion of nacre, are disturbed or displaced due to damage to the shell or a foreign invader.
Most valuable natural pearls form in nacreous shells from the Pteriidae family. Non-nacreous pearls also occur, often in gastropods, and can be very valuable. Examples of non-nacreous pearls include those found in conch, melo melo and abalone shells.
The growth of cultured pearls requires human intervention and care. Today, most of the mollusks used in the culturing process are raised specifically for that purpose, although some wild mollusks are still collected and used.
To begin the process, a skilled technician takes mantle tissue from a sacrificed mollusk of the same species and inserts a shell bead along with a small piece of mantle tissue into a host mollusk’s gonad, or several pieces of mantle tissue without beads into a host mollusk’s mantle. If a bead is used, the mantle tissue grows and forms a sac around it and secretes nacre inward and onto the bead to eventually form a cultured pearl. If no bead is used, nacre forms around the individual implanted mantle tissue pieces. Workers tend the mollusks until the cultured pearls are harvested.
There are four major types of cultured whole pearls:
Akoya Cultured Pearls
Akoya cultured pearls are the most familiar type of saltwater cultured pearl to most people in Canada, the U.S and other western markets. Many customers think of white or cream coloured akoyas as the classic pearl used for jewellery, especially single-strand necklaces. Akoya pearls are produced in Japan, China and Vietnam.
South Sea Cultured Pearls
Australia, Indonesia, and the Philippines are leading sources of these saltwater cultured pearls. South Sea cultured pearls can be white to silver or golden, depending on the type of oyster. Their large size and thick nacre, due to a long growth period, plus their limited critical growing conditions are all factors contributing to their value.
Tahitian Cultured Pearls
Cultivated primarily around the islands of French Polynesia (the most familiar of these is Tahiti). These saltwater cultured pearls, sometimes referred to as black pearls, have a wide colour range. They might be gray, black or brown, and they can have blue, green, purple or pink overtones.
Freshwater Cultured Pearls
Freshwater cultured pearls are the most commonly produced pearls, and they are one of the most popular pearl types among shoppers and jewellery designers. This is due to their remarkable range of sizes, shapes and colours, plus their commercial availability at lower price points. They are usually cultured in freshwater lakes and ponds, often with many pearls grown in one oyster. China is the leading source for freshwater cultured pearls.
What is the difference between saltwater pearls and freshwater pearls?
Depending on the place of their origin, all pearls can be divided into two categories: saltwater pearls and freshwater pearls. Saltwater pearls come from seas and oceans and their colour can be white, soft grey, faded golden, deep grey and purple. However, the most common and the most popular colour of saltwater pearls is soft pink. Freshwater pearls have their origins in streams, lakes and rivers and can naturally be white, beige, pink, lilac or peachy. Freshwater pearls are also often dyed, which results in a wide variety of nuances to choose from.
How do I take proper care of my pearl jewellery?
Pearls are more durable than most people think, however, to keep them in optimal shape it is best to avoid exposing pearls to harsh chemicals (perfumes, hairspray, cleaning agents, etc.), pearls should be kept away from sharp or rough objects to avoid scratching, and they should be wiped clean after wear and stored in a soft pouch or case. It is best not to store pearls in dry hot environments, and pearl necklaces may need to be restrung periodically as the silk string can darken, stretch, or wear thin over time. Most pearl necklaces are knotted; so should they break, only one pearl will come loose.
(Adaptation – Text courtesy of GIA Different Pearl Types & Colors | The Four Major Types of Cultured Pearls | GIA)