Freshwater pearls form in different mollusks, not oysters, from lakes and rivers. Cultivated freshwater pearls occur by opening the mollusk shells just enough to slit the mantle tissue and insert small fragments of mantle tissue from another mussel. This immediately starts the production of nacre. The cultivation process is much simpler for freshwater pearls than saltwater pearls and the mussels can grow pearls a second and third time without intervention. Freshwater pearls have thicker and more irregular nacre resulting in different shapes. These off round shapes, referred to as baroque pearls still have a beautiful high luster and although they sell for far less than the saltwater pearls, should not be regarded as lower quality. Saltwater Pearls Saltwater pearls are cultivated in oysters in the oceans of China and Japan. An oyster can only produce one pearl, unlike the freshwater mollusks. Because of the more complex techniques, the risks to harvest and the cost to do so, this makes saltwater pearls more valuable and expensive than freshwater pearls. Cultured Pearls The earliest cultured pearls came from Japan and were called Biwa Pearls, as they were produced in Lake Biwa. Eventually, pollution decreased the production of these pearls in Japan. Seizing the opportunity, China is now considered the leading producer of cultured pearls in the world today. Cultured pearls are also created in other regions of the world. The temperature, depth of the water, the species of the oyster and the type of foreign body inserted into the shell determines the shape, color and size of the pearl. Akoya Pearls Akoya Pearls are cultivated in the oceans of Japan and China and are the best known and most popular pearls. Akoya pearls take from two to fours years to form, before they can be harvested. These mollusks can only be harvested once, unlike the freshwater species. The average size of the Akoya pearl is 2-9mm and is usually found in hues of creamy white with shades gray and pink. Japanese Akoyas are usually larger (over 7mm) and therefore more valuable. Rarely, will an Akoya pearl exceed 10mm in size. Tahitian Pearls and Black Pearls These are some of the most sought after pearls in the world. Cultivated in the oceans of the South Pacific, these pearls are harvested from the black-lipped oyster (pinctada margaritifera). They are found in hues of black, silver grey, purple and the rare, peacock hues of bluish-green. These pearls are larger than the Akoya and average between 8-12mm. These pearls are also more expensive than the Akoya pearls. They are considered exotic and have been revered as magical and mystic in nature. Australian or South Sea Pearls The South Sea Pearl is harvested from the southern oceans bordering Australia and Southeast Asia. The process in which these pearls are cultivated is very complex, limiting the number of pearls, which in turn creates a greater demand and higher prices. These pearls range in size between 10-20mm and are usually light shades of white, gold, pink, and blue. South Sea Pearls are the most expensive type of pearl. Mabe Pearls Mabe pearls come from the oyster referred to as Pteria penguin and are assembled from a cultured blister pearl. A large half bead is attached inside the shell between the mantle and the mother-of-pearls and the mollusk’s internal shell. The blister pearl that is formed is removed and filled with wax or glue for stability. They are then usually backed with mother-of-pearl. Less expensive mabe pearls may be backed with plastic. Keshi Pearls Keshi Pearls in Japanese mean “poppy seed”. Keshi pearls are unique in that they are the by product of the pearl cultivation. Keshi Pearls form without intervention in the soft tissue of the mollusk. They are irregular in shape (baroque) and contain no nucleus. Although they form naturally, they are only found in cultivated mollusks. Keshi pearls come in, not only different shapes, but sizes and colors, as well. They are noted for their high iridescence and luster, but are less expensive than round pearls. Biwa Pearls The term Biwa may be used to reference freshwater pearls in general; however, the Biwa Pearl originated from the Biwa Lake in Japan. Due to progress and environmental pollution, the mollusks are near extinction, making these pearls increasingly rare to find today. Abalone Pearls Abalone Pearls come from the gastropod mollusk, Haliotis. Because this mollusk is hemophiliac, it is very difficult to culture them, as they will bleed to death, if they are nucleated in the same manner as other mollusks. The cultivating process is similar to other pearl producing mollusks, but special attention has to be given in order to prevent damage to the internal tissue. The inner mother-of-pearl shell of the abalone has an intense and deep luster producing mixed hues of lavender, orange, pink, green, blues and silver. Rarely are Abalone Pearls symmetrical and most are in the shape of a horn. Abalone Pearls are not as popular in the United States, as they are in New Zealand and Australia, due in part to the farming and marketing in New Zealand. Conch Pearls Conch Pearls, technically, are not pearls since they contain no nacre. These “pearls” are made from calcareous concentrations, similar to kidney stones in humans. There is no method for culturing these gems, so every one is natural and extremely rare. (Only one in 10,000 conchs produces a pearl. Less than 10% are of gem quality). They are normally oval in appearance and 3mm or less in size. Their colors range from pink, brown, white, and gold, with salmon, orange, and pink being the most popular. The color will fade over time if worn in the sunlight, so it is recommended that this gem be worn primarily in the evening. It is rare that any two are alike, so matching pearls for strands or earrings is very difficult. Melo Melo Pearls The Melo Melo Pearl also comes from a shell found in the South China Sea and not a mollusk. No technique has been discovered yet to successfully culture these gems, so all Melo Melo Pearls are natural. They range in colors from tan, dark brown and orange and will also fade over time. They are usually very large and generally very round. They are not well known outside of Asia. Scallop Pearls Similar to the Conch Pearl and the Melo Melo Pearl, the Scallop Pearl comes from a bivalve shell. The Scallop pearl is very rare and life long scallop fishermen have found maybe a handful of these unique gems. Scallop pearls have been found in oval, round, button and tear drop shapes and they represent exquisite hues of plum, orange, pink and burgundy. Other Pearls… Mikimoto Pearls Mikimoto Pearls is a brand name and not a type of pearl. Kokichi Mikimoto, the son of a Japanese noodle restauranteur, was the first person to culture and patent the technique for producing round pearls, in the 1920’s. He had previously been awarded the patent on the process for culturing Mabe Pearls in the late 1890’s. His tireless advocacy of new culturing techniques opened new markets all over the world and it has been said that his efforts created the pearl industry as it is today. Imitation or Simulated Pearls Imitation pearls are pearls that have been manufactured and man made from glass, plastic, shell, and ceramic, among other things. They are usually coated with a finish that gives them the pearl like iridescence, but, none to compare with a real pearl. Well known simulated pearls are “Majorca” Pearls, made in Spain, using glass beads surrounded by a fish scale paste from the North Atlantic. They are very lovely, but they are not pearls. |
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