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PEARLS
Consist of calcium carbonate, aragonite, water and concholin. The concholin is what binds the layers together.
Consist of calcium carbonate, aragonite, water and concholin. The concholin is what binds the layers together.
- They have a hardness of 2.5-4.5. They are very tough. The luster is pearly.
- Are produced by oysters(sea mollusks) and freshwater mussels.
- They form by placing calcium carbonate around an irritant.
- A natural pearl has an irritant that is naturally there such as a parasite or even a piece of sand.
- A cultured pearl has a mother of pearl bead with a piece of mantle tissue or a piece of mantle tissue inserted into the mollusk.
From a historical sense pearls have been around a very long time and have been one of the most treasured of the organic gems. They were used for taxes in China. Sewn on clothes in Persia(Iran). During the Middle Ages they were exclusively a royal gem. Some of the earliest references to pearls were made to Ceylon and India. In fact, it is documented here in ancient writings concerning the association of pearls with weddings! So, that is very possible where the tradition of brides and pearls got started.
During the early twentieth century pearl prices were too high for mass ownership but by the 1920's American women were owning lots of different pearl jewelry.
Two factors occurred in the 1930’s that affected the pearl market, one was the depression and the second was the introduction of the cultured pearl. Kokichi Mikimoto was the creator of this technique. At the age of 94 when Mr. Mikimoto was interviewed, he was asked what contributed to his health? He said he owed his good health to the two pearls he swallowed every morning since the age of 20! Tiffany’s did not start carrying cultured pearls until 1956! Which is sad because Mikimoto died in 1955. I bet almost everyone of you have a strand of Mikimoto’s either through your own ownership or from your mothers! Most pearls on the market today are cultured.
| CULTURED PEARLS Started in the 13th century with the Chinese implanting Buddha figures in the mollusks producing blister pearls. Different techniques were experimented with and in 1896 Mikimoto patents method for cultured pearls.In 1908 Mise and Mishikawa develop a different method for culturing pearls.In 1916 again Mikimoto patents another method for cultured pearls and this method was the first used in commercial production. So, how is this done? Baby oysters are held for about three years until they are mature. Then a mother of pearl bead is placed inside the tissue(known as the mantle). They are then placed in buckets or cages and suspended from rafts about 10 to 7 inches in the water. This occurs at various saltwater farm areas. It can take 3 to seven years for a pearl to grow properly. Because after the mother of pearl bead is implanted the oyster treats it like an irritant and thus nacre (coating around a pearl) is constantly placed around it. But, they only grow so fast.It is reported that now it can take only two years to grown a pearl.After the pearl is ready, it is removed and then sorted and graded. TYPES OF PEARLS Akoya is the most known, it is the most common pearl farmed in Japan and also is being produced in China now. It seems that more Japanese farms are shifting towards the warmer Chinese waters, where pearls take almost half as long to grow. Sizes range from 2mm to 11m with 10mm and 11mm being very rare. They implant 1 to 5 nucleations in the oyster and it takes from 8 months to 2 years for a pearl to grow. South Sea are grown off the coasts of Australia, Indonesia and the Phillipines. Are one of the most expensive can grow 9mm to 20mm. They come in primarily whites, yellow, yellowish orange, blue and some black tones. The overtones are rose, green and blue. The white are silvery but not as lustrous as the Akoya. The oyster can only produce one pearl at a time with growth taking almost 2 years! So if you see a massive supply of someone stating the pearls are south seas and inexpensive, think twice. Tahitian are grown off the islands of French Polynesia. Usually 8mm - 14mm in size. They come in colors of many shades of gray, brown, blue to green, purple and yellowish green. Peacock is is a dark green to blue gray with overtones of rose to purple. Aubergine is a dark grayish purple and pistachio if a yellowish green to greenish yellow. With a nice thick nacre as a rule. Only less than half of Tahitian pearls are round!!! The oyster can only produce one pearl at a time with growth taking over 2 years. So, again if you see a massive supply of someone stating the pearls are "Black South Seas" or Tahitians and inexpensive, make sure you get some validation.These pearls are expensive because of the tremendous care in their growth! Burma grows large 10mm & up are rare and costly. Blister Pearls - these pearls are grown attached to the inside surface of the shell of the oyster or freshwater mussel. When they are removed from the shell, one side is left flat and has no pearl like coating. Mabe - these pearls are assembled blister pearls, they are cultured by gluing a half-bead nucleus against the inside of the oyster shell so they have a hemispherical appearance. Once the mollusk has secreted nacre over the bead, the blister pearl is cut from the shell and the bead is removed. The hole that remains is empty so it is filled with paste or wax. Sometimes even a bead can be put into the empty hole. It is then covered with a mother of pearl backing. These are delicate so they are used in earrings, rings, pendants and brooches. A three quarter or half pearl can be made of two things, a bead that is flattened on one side and placed against the mollusk shell similar to the mabe and blister pearl or a round pearl that has had a portion cut from it to eliminate a blemish or a shape that is not perfect. Biwa - these are freshwater pearls from Lake Biwa in Japan. They have a higher luster and smoother than the Chinese freshwaters. A lot of times you will see freshwater pearls advertised as Biwa and that is false since only pearls from Lake Biwa can be called as such. Unfortunately pollution is affecting the production of this type of pearl. Freshwater - these are pearls that are cultured via freshwater mollusks found in rivers and in lakes. Mantle tissue is inserted in the mantle. The pearl is basically almost all nacre. Even though now they use a rounded potato pearl(freshwater) and piece of mantle tissue to get the larger sizes. So, they are still all nacre. It has been said that they also use a mother of pearl bead as an implant in the larger sizes but the pearls that I have cut in half, all have the potato implant. They are by far the least expensive. You get a variety of different shapes(potato, rice, corn, stick, semi-round etc.) sizes, natural colors(pink, mauve, peach, lavender, gray, bronze, yellow) and styles with these pearls. The reason for the abundance on these pearls is that they can implant 40 to 50 tissue nucleations in one mussel and they take anywhere from 4 to 6 years to grow. Keishi - are formed naturally in cultured pearl oysters, they are very tiny in size and sometimes referred to as "seed pearls". Now that China is producing the 2-3mm in round sizes we will probably see this term used for the freshwater small rounds. Major Pearl Producing Centers Japan is the largest producer of saltwater pearls however China is entering the market. China is the largest producer of freshwater pearls since the mid-1980's. At first they used mollusks that produced pearls that were hard to tell the difference from the Biwa freshwaters. In the early 80's China changed to a faster producing mollusk(3times as fast) and the inexpensive rice pearl came about. Market price dropped and needless to say the quality wasn't that great. In the late 1980's several major Japanese firms went under because China upped it's production to an estimated 150 tons. Even some American firms made a retreat to saltwater pearls! In the 90's China has started on concentrating on better pearls once again. The beauty of the the Chinese pearls is that they take a piece of mantle tissue as the irritant thus resulting in a pear with a thick nacre. They have semi-round freshwaters now that are very affordable. With sizes reaching up to 12mm round and even bigger in other shapes! In the round sizes they fashion the well known oval potato pearl into a round implant and the result is an almost all nacre pearl. They are also harvesting the Chinese Akoya. We have freshwater pearl farms in Tennessee's Lake Kentucky. The world's largest supplier of cultured pearl bead-nucleus material is located in that area. Tennessee Shell Co. once owned by John Latendresse, who now owns the American Pearl Co. They come in various shapes and sizes, even rounds are farmed. There are plans for other pearl farms throughout the country even in California. American cultured freshwater pearls are never dyed, bleached or enhanced. Abalone pearls are one of the rarest. They come in an array of colors with a peacock blue being one of the rarest. They are found in the abalone off the Pacific coast of the US, Mexico, Japan, New Zealand and Korea. Then you have the debatable conch pearl which is considered by most gemologists not to be a true pearl. True pearls are considered to be produced only by a bivalve mollusks and this is not the case with the conch pearl. However, it is in a category of it's own. It is found in the great Conch throughout the Caribbean. Colors range from brownish-white, white, yellow to shades of pink. Needless to say they are very expensive! COLORS Pearls come in a variety of colors (depending on their origin) from yellow, white, silver, pink, cream, gray, black, pink and other colors. Different minerals affect colors and believe it or not pollution can have an effect on the colors. They can be dyed (which is not stable) and (irradiated-black, gray, silver and rainbow colors-stable first introduced in the 50's to treat cultured pearls), bleached to remove impurities, nucleus can be dyed and the most unstable the use of silver nitrate to turn pearls black (which makes the nacre softer and less durable). Different countries like various colors, we seem to prefer white, creams and the pinks. In South America for instance they love yellow. CRITERIA FOR JUDGING PEARLS Luster - the pearls should have a high luster(shininess), orient(iridescence-looks like a circular rainbow on the pearl), the more the more expensive. Graded as high luster, medium luster, low luster and very low luster. Color - in white pearls it is personal choice but rose is usually preferred, this is affected by something called overtone (powder on a woman's face). Common overtone colors-rose, silver, blue and green. Blue being the rarest rose being the most common. More rose the more value, more green lower value. In black pearls overtone is usually green or pink. Colors (bodycolor)are rose, white, cream, yellow or gold and gray(for saltwater cultured). So, when we describe a pearl's color we are talking about the combination of bodycolor and overtone. A white-rose pearl would be white in bodycolor with a rose overtone as would be silver-white(silver overtone) or blue-gray(blue overtone). Then we have the colored freshwater pearls, these are judged by the depth of color that we see and intense lavender will have more value than a lighter shade(unless of course it is a larger size, the rarity plays in) Surface appearance - freedom from blemishes, cracks, spots, blotches,"orange peel" effect. Graded as clean to heavily blemished. Shape - rounder the more expensive. Can be defined as round, semi-round, off round, oval to baroque,which must have an interesting shape(for example the many that I have seen look like a pear or a tadpole), not just an out of round pearl). Size - most popular sizes in salt water cultured are 4.6mm to 6mm. Of course the bigger the more expensive! This is true for all pearls! Nacre thickness - is judged by looking at the bead hole and as a rule you can see the separation between nucleus and nacre. Thickness ranges from very thick at least .5mm, medium .35mm to very thin at .25mm. This is judged on a basis of the ratio of the nacre to the bead. If a pearl has a high luster, uniform iridescence it usually has a thick nacre. If the pearl is chalky and dull it is usually thin. Rarity - matched pearls. CARE OF PEARLS Pearls should be wrapped in something when stored. However they do need moisture so a sealed container which keeps moisture out is not recommended. Avoid contact with vinegar, ammonia(found in most commercial jewelry cleaners), bleach, ink, hairspray, perfumes and cosmetics. These substances will spot or break down the surface of the pearl. When putting your pearls away it is suggested that you wipe with a hot damp towel to remove body oils. You should wash your pearls on occasion. In mild soapy water, not detergent. After washing rinse in clear water and wrap them in a cotton towel to dry. You can use a soft brush to clean around the knots. It is recommended that you have your pearls re-strung once a year if you wear them a lot. This keeps them from rubbing against each other and going all over the place if they break. Small pearls do not have to be knotted since the knotting detracts from the appearance. |
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