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General – Natural vs. cultured pearl.

Natural pearls are not gems, but instead are formed either in saltwater (in the ocean, sea, gulf or bay) by oysters or in freshwater (in rivers, ponds or lakes) by mollusks. They are such a rare sight today that they are valued almost the same as very precious stones. Both saltwater and sweet-water types begin creating the pearl when a foreign irritant enters the shell and cannot be emitted. The irritant may be a miniscule snail, a bit of dirt, a tiny sea parasite or even a piece of clay or mud. In an attempt to protect itself, the mollusk will begin coating the irritant with a protective layer called ‘conchiolin', over which another white layer builds up. This white layer is the first layer to form the actual pearl and it is made up of nacre (pronounced NA-ker). Nacre is basically composed of a multitude of microscopic crystals each aligned perfectly to reflect light across the surface of the burgeoning pearl. The best quality pearls are those with the most layers of nacre, each deepening this quality and allowing the pearl to react to light in a rainbow effect. This is a slow, painstaking process that takes many years to complete and the one obvious advantage with natural pearls is their thickness. The patient work of the oyster or mollusk finally produces a tiny little nucleus coated many times over and thick with opalescent nacre.

Cultured pearls, as opposed to natural ones, do not begin their existence by accident. Cultured pearls are mollusks into which irritants have been put in deliberately to create a pearl. This is still a painstaking process that requires years- first to grow the mollusk to the appropriate size and later on to allow it to coat the irritant. However, cultured pearls do not begin with a tiny irritant, but with a deliberately large ‘nucleus' and they are almost never allowed to spend years and years at the task, and so they are smaller, with thinner layers of nacre. Almost all pearls being sold today (about 95%-99%} are cultured pearls and are not natural. This is particularly true of the U.S that sees almost no natural pearls in its market.

The criteria for evaluating pearls:

  1. Nacre:

There are several factors that must be considered when evaluating a pearl for quality. First and foremost is the importance of the nacre. Rare, natural pearls are made up almost entirely of nacre, as the basic irritant that begun their process was microscopic, but cultured pearls are made up of a large, artificial irritant and it's up to the quality of care given to them throughout the cultivation process to determine the thickness of the nacre. Pearl producers wash the oyster periodically, keep up the food supply in its environment and try to maintain a constant temperature in an attempt to ease the difficulties of the oysters work. Faster is defiantly not better in the culturing process , but like most things in today's world- quality is sacrificed for commercial gain. In the first decades of pearl culturing the pearls were left to grow for several years and they reached wonderfully large sizes. Since the late 1970's, culturing is stopped after only a few months and small pearls are produced with very thin nacre coatings. In some very poorly cultivated ones you will see the nacre chip off the nucleus. Generally, the thickness of the nacre determines the pearls longevity and the quality of the nacre determines the amount of luster that the pearl has. Without a thick coating of nacre the pearl is left unprotected and it will easily chip or fracture with time. Without good quality nacre that lets light travel through, the pearl isn't able to create uniform layers or the layers form without proper alignment. The result is lower luster and poor crystallization of the nacre. This automatically reduces value, which is primarily based on the pearls gloss and deep sheen.

Quality and thickness of nacre:

This leads us directly to the second factor in pearl evaluation. Quality and thickness of nacre are the basic components of ‘luster' and ‘orient'. Luster refers to the intensity of the pearls reflection. This is something you can examine for yourself, while holding up a pearl to the light. If the images reflected onto the pearls surface are clear and well-defined, the pearl has high luster. Orient refers to that special, intrinsic quality pearls have- that of iridescence. If the pearl you are holding has a great play of color just beneath its surface, and if it maintains this effect also in dim light, then it has orient. Both these qualities combined produce the final result, with pearls possessing high luster and orient rated the most valuable. Also important is the surface quality of the pearl. The fewer and smaller the blemishes on the surface, the more it will cost. Though its considered normal that a strand of pearls will have atleast some blemishes, the best quality are perfectly smooth.

Third there is the question of size . Pearls range in a wide array of sizes and each category of pearls is sold by different standards. Natural pearls, for example, are sold by weight. They are extremely expensive because of their rarity and the set measurement for natural pearls is grains and carats. There are four grains to each one carat natural pearl. Cultured pearls, on the other hand, are sold by size. They are measured in millimeters by the diameter of each pearl, and there is a price-range for several diameter-length groups. Large cultured pearls, those that are over 7.5 millimeters in diameter, are rare and expensive. Anything smaller than that is reduced gradually in value with 2 millimeters considered the smallest acceptable diameter.

The fourth factor is shape . Many people seem to think that pearls all form in round symmetry, when in fact there is a whole range of pearl shapes. There are three basic shape-types; the most prized are the spherical, round pearls with those of best symmetry and proportions being valued most. Less valued are the symmetrical pearls, which aren't round but instead form in pear or drop shapes. These are valued for symmetry and good proportioning, as well. The third and least expensive are the baroque shapes that are asymmetrical and irregular. Baroque-shaped pearls are sold as whole 16-18 inch strands, with smaller 7.5-8 mm pearls selling for $500-$1300 and larger; 8.5-9 mm pearls selling for about $700-$2000. If you are buying a necklace and cannot choose each pearl yourself, examine also the ‘make' of the piece to see if each of the pearls was matched perfectly in shape to the entire piece. This is important in all pearl jewelry and the more precise and homogonous the necklace, the more expensive it will be. The price range for white, silver or cream-colored round pearls in 16-18 inch strands is dependent on their diameter size. The very large pearl strands of 9-10 mm cost about $5000-6000 to $28,000. Slightly smaller 8-8.5 mm pearl strands will cost about $2000 to $11,000, the 7-7.5 mm will cost $1200-$6000 and the smallest 6-6.5 strands about $1000 to $3000.

Lastly there is the question of color , and different colored pearls can differ hugely in cost. This is also comprised of two fundamental elements- basic body color, which can be white, black or yellow, and basic tone or tint, which interweaves into the body color and influences it. In the same way that gems are evaluated for hue and undertone, pearls are evaluated for body color and overtone. For example, white pearls with pink overtones are the most expensive type of pearl besides precious black pearls. On white pearls, yellow or greenish overtones almost automatically reduce price. White or very light pink saltwater pearls always sell for more than yellow saltwater pearls. In naturally black pearls, the most prized are those with different color overtones, so that black nacre with gray overtones will sell for less than black with pink, blue, green or purple overtones that give more luster to the pearl.

Pearl pricing:

Freshwater pearls occur naturally, just as saltwater pearls do, but most of the pearls in the market are cultured- not natural. Some very few natural freshwater pearls have been found in the rivers of the U.S, Ireland , Scotland , Austria , France and Germany , but today this tiny market has very little importance. Freshwater pearls occur in a wide array of colors, including white, gray, blue, pink, lavender, violet, purple and even orange. They range from very light to very dark tones. Since cultivation is quite easy, its being done in many parts of the world today and therefore freshwater, cultured pearls are much less expensive than saltwater pearls. Freshwater pearls usually look like small, wrinkled rice grains. They range in price from about $5-$30 for 4 and 5 mm pearls. They rarely form in round shapes, though they are large in size and the very few who do form roundly are extremely expensive.

Only natural, freshwater pearls truly rival the prices of natural saltwater ones, because they have a tendency to form in pristine white color and this quality is very marketable. China is the world's largest producer of freshwater pearls, alongside the U.S and Japan . Among the freshwater varieties there are Japanese Biwa pearls cultured in the Biwa Lake, Japan, which are well-known for their fine quality. Ireland, China, the U.S are also producing freshwater pearls now, using mussel type mollusks for efficiency and speedy production, such as the ‘Angel-wing' pearls from the Mississippi River. There are also Tahitian black pearls. These are called ‘black' pearls, but in fact come in a variety of gray, blue-gray, brownish black or green-black to absolute black natural coloring, produced from the black-lipped saltwater oyster unique to the waters of French Polynesia and the Cook Islands . The rarest and most expensive type is black with iridescent green overtones that give the pearl a luminescent quality. They average in size from about 8 or 9 millimeters in diameter in drop shapes. Round shapes are extremely rare for this type of pearl. Black pearls are sold individually and not in strands. They each cost about $250-$1000 for smaller pearls of 8.5-9 mm diameter. The larger, 10-10.5 mm black pearls cost about $420-$1400 and even larger, 11.5-12.5 mm pearls cost $950-$2400.

Saltwater pearls are generally more expensive than freshwater pearls. The greatest percentage of natural saltwater pearls is harvested in the Red Sea, the Persian Gulf and the Gulf of Manaar . The most famous are Japanese Akoya pearls, which are regarded as being the best quality pearls produced from saltwater oysters. Today China has also begun culturing akoya pearls, though they are even smaller than the Japanese variety. They are usually perfectly round and have very high luster. All akoya pearls produced before 1960 were left to cultivate for atleast two and a half years, allowing them grow to magnificent sizes, while today most pearls are left to cultivate no more than half a year. Unlike South Sea pearls, dyeing is often accepted in these pearls because natural akoya don't form in dark colors. Dyed South Sea pearls aren't accepted because they compete with authentically black Tahitian pearls and this confuses buyers.

A second well-known variety of saltwater pearls are White South Sea pearls that are produced in Australia , though the Golden variety is produced the Philippines and Indonesia . They come in a whole range of colors; from pure white, to pink tones, pale yellow tones, intense yellow, and gold. White South Sea pearls cost about $1200-$4000 per pearl for 11 and 12 mm diameter. They are not sold in strands because of their large size. Larger, 12 and 13 mm pearls each cost about $1500-$4500 and 14 and 15 mm pearls cost about $3000 to $9500.

These are much larger than the smaller akoya pearls, which almost never exceed 10 mm in diameter. South Sea pearls usually start at 10mm and can get to sizes of a whole foot in diameter. The average is about 11 to 13 millimeters in diameter and they lack the fantastic luster and perfectly round shape that akoya pearls have. In spite of this, they are extremely expensive to buy and their huge size makes them even more expensive. Generally the rule is that yellow saltwater pearls will always sell for less than white or pink ones. The Golden South Sea found near Indonesia pearl breaks this rule, providing the gold color is evenly distributed and intense. The rarest type of South Sea pearl is the white with pink overtone and the white with silver overtones. Less pricy are the pale yellow or ‘white-yellow' pearls.

Today new kind of affordable pearls are being sold. ‘Mabe' pearls and ‘three-quarter pearls' aren't real pearls and so cost far less. Mabe are cheap ‘blister' pearls, usually dome-shaped. They are called ‘blister' because a thin membrane of nacre forms inside the oyster, attached the interior of its lining, instead of an actual pearl. This hollow pocket of nacre is removed from the oyster and then filled with epoxy to harden it and retain its shape. Finally it is backed with a mother-of-pearl backing to produce a compound pearl that is suitable for earrings or brooches, though it should be protected with a sturdy mounting, as they are vulnerable to breaking. Solid Blister pearls are similar to Mabe pearls, but they are not man-made. Instead, they are dome-shaped, freshwater pearls from Tennessee that are famous for their unusually high luster and orient.

Pearl authenticity

Lastly there is the question of authenticity. Imitation pearls, which are so widespread it would be impossible to give an estimate of the percentage they take from the whole pearl market, have nothing to do with either natural or cultured pearls. They aren't formed in mollusks, but are completely artificial. Usually they are made of glass or plastic, though no treatment has solved the problem of depth. Real pearls don't only shine across the surface of the pearl, they also have depth to the shine that is created from one thin layer atop another and multiplied a hundredfold. They have a luster that hasn't yet been duplicated with real proficiency, despite the fact that imitation pearls have been around for centuries. Some imitations are presented as real pearls by the names: “Tecla pearls”, “ Red Sea pearls” ( that are really coral beads dyed to look like pearls), “Girasol pearls” (imitation), “Atlas pearls”, “Laguna pearls”, “Majorica pearls” and “Conch pearls”. In fact, none of these are authentic pearls. The most expedient way to test a pearl for authenticity is to run it very gently along your upper teeth to feel its texture. Imitation pearls will have an absolutely smooth feel to them, as they are beads dipped into a coating. Real pearls will feel gritty and sandy as they are constructed with layers of microscopic sea-sand. Today there are maybe one or two imitation pearls that will be able to fool you, being made from very fine coating materials, but for the most part this simple test is effective. Treated pearls, on the other hand, are acceptable as long as you are informed of their treated status and pay the reduced price for them.. They are usually dyed or treated with radiation.

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