Types of Pearls
The pearls differ in their luster and mysterious colours depending on the way it has been produced:
Natural Pearls
Natural pearls are formed naturally by the oyster. After three or more years, a Natural pearl of good size (4-12 mm) can be found inside an oyster. The natural pearls produce only single pearl at a time. These are extremely rare and hence, are known to be expensive. Natural pearls are sometimes worth around 10 times more than their cultured pearl equivalent. Due to their natural origin, natural pearls have many shapes: baroque or odd-shaped, drops, ovals, buttons and -very rarely- round.
Cultured Pearls
Cultured pearls are formed by the joint efforts of Man and Mussel, as opposed to a natural pearl. Farmers implant a fine bead into the oyster where it cannot be expelled. The oyster does the rest and creates its lustrous masterpiece – the cultured pearl. For each oyster, 1 pearl can be got. As natural pearls are rare, people have started dealing with cultured pearls these days. The majority of pearls that are used in jewellery today are farmed and not naturally grown.
Types of Cultured Pearl
1) Akoya: Akoya, one of the most familiar type of cultured pearls, are round, white and lustrous gem. They are a symbol of elegance and beauty. They are saltwater pearls and come from the smallest of all pearl oysters. Akoya’s from Japan and China are grown in pearl oysters and depending on the size of the oyster, they rarely grow more than 9mm in size. They are known for their lovely orient and warm colour.
2) South Sea: South Sea pearls are among the largest commercially harvested cultured pearls in the world. A South Sea pearl can range from 9 - 20mm with an average size 13 mm. Their colour ranges from silvery white to gold. They are quite costly due to their size and rarity. They are also identified by their thick nacre or ‘mother of pearl’ (an organic mixture of Calcium carbonate and crystals).
3) Tahitian Black Pearl: The natural black colour of the Tahitian pearl comes from the black-lipped variety of the Pinctada maxima oyster. They range from 10mm size and above, which has made them one of the most sought-after, expensive pearls in the world. These pearls are seldom round; they come in a variety of shapes and a range of metallic colours - from grey to black to green, peacock-blue and aubergine. The “Tahitian pearls” are found around the islands and atolls of the French Polynesia.
4) Mabe: Mabe (pronounced Mar-bay) are known as half-pearls or blister pearls. They are large hemispherical cultured pearls grown against the inside shells of oysters instead of within the body. Because of their hemispherical shape, they are most popular in earrings, rings and brooches. The size of mabe pearls varies from 12 to 20 mm in diameter. Mabe cultured pearls are less expensive than regular round cultured pearls.
5) Freshwater: Freshwater pearls, unlike other pearl types, are cultivated in mussels, not oysters and are found in fresh water lakes, rivers and ponds of China, Japan, North America and Europe. Triangle Shell mussel is a common source of Freshwater pearls and can yield between 30-40 pearls. Fresh water pearls generally are elongated in shape and have a milky translucent appearance. Their wide range of interesting shapes such as freeform, rice shaped, off-round or spherical and colours ranging from milky white to peach, pink and lavender, make up in fashion appeal for their relatively affordable value.
6) Keshi: Also known as seed pearls, these tiny cultured pearls can be as small as a grain of sand and form accidentally in many cultured pearl oysters. Many Keshi pearls are curved, while some can be rock-shaped baroques measuring 4MM to 15MM. Keshi pearls can form in either saltwater or freshwater mollusks.
7) Baroque: Baroque pearls are pearls with an undefined, irregular shape and almost never round. Freshwater pearls are most commonly baroque. Due to their shapes, baroque cultured pearls are often less costly than round cultured pearls.
Imitation / Synthetic pearls
Imitation Pearls are usually a coated glass bead. Most have a high luster, but not the depth of luster seen on high quality cultured pearls. Some imitation pearls (also called shell pearls) are simply made of mother-of-pearl, coral or conch shell, while others are made from glass and are coated with a solution containing fish scales called essence d'Orient.
Types of Synthetic/Imitation Pearls:
1) Bathed pearl: A mother-of-pearl core coated with a mixture of plastic enamel, lead carbonate, mica, and titanium dioxide, then with a film of iridescent nylon.
2) Bohemian pearl: Cut and buffed mother-of-pearl protuberance.
3) Glass pearl: Glass bead dipped or sprayed with pearlescent material, or hollow glass bead filled with pearlescent material. Wax-filled pearl simulants are hollow glass beads coated with essence d'orient and filled with wax.
4) Mother-of-pearl pearl: Crushed nacreous shell powder, sintered into the desired shape.
5) Plastic pearl: Plastic core coated with pearlescent material.
6) Roman pearl: Alabaster core coated with pearlescent material.
7) Shell pearl (1): Cut, buffed, and sometimes dyed nacreous portions of mollusc shells. Variations and alternate names include cat's-eye pearl, coque de perle (from nautilus shells), mother-of-pearl pearl (from mother-of-pearl), and hinge pearl (from the hinge of bivalve shells).
8) Shell pearl (2): Spherical shell core coated with pearlescent material