Блог о жемчужине Южного моря

  • Colour in cultured pearls has many causes

    Colour in cultured pearls has many causes | The South Sea Pearl
    Colour in cultured pearls has many causes, namely organic pigments and the water reservoir where the pearl shell is grown (sea water or freshwater) that has different manganese (Mn) concentrations with impact on nacre's colours. The mollusc species is, of course, one of the most important factors in this process, specially the donor specimen that provides the mantle tissue that is inserted in the gonads or mantle (depending on the culturing method) of a productive pearl mollusc for the formation of the cultured pearl sac. In Fiji, the local pearl oyster Pinctada margaritifera typica has mantle tissue cells that secrete unusual earthy coloured nacre (seen in the oysters' mother-of-pearl shell interior), and thus the colours of those cultured pearls are also expected to be coloured in such a way. Fiji has been producing natural color beaded cultured pearls, with ocasional non-bead "keshis", in relatively limited numbers since 1999 when Justin Hunter, a biologist and visionary, started his blue economy project with a pearl farm in his home land in Savusavu, Fiji, promoting sustainable luxury through marine cultured pearls. Photos © J. Hunter Pearls Fiji
    #pearls #pearljewelry #luxury #gemology #jewelry
    Continue reading
  • Fireball Fresh-Water Cultured Pearls

    Fireball Fresh-Water Cultured Pearls | The South Sea Pearl
    Fireball pearl is the trade name for a type of beaded freshwater cultured pearl. Pearl farming in freshwater started to commercially develop in Japan in the 1960s in Lake Kasumigaura based on a new type of hybrid mussel made between the Japanese Hyriopsis schlegelii, and the Chinese Hyriopsis cumingii. These cultured pearls, known in the trade as Kasumiga, had small production and today only three farms are reportedly in operation. In the beginning of the new millennium, this hybrid was used again with an innovation by inserting a round 9 to 12 mm shell bead as a nucleus into an existing pearl sac that resulted from a previous culture in the mussel's mantle. The process is known as CBSB (coin-bead/spherical bead) referring to the two stages of this long process. This second generation beaded cultured pearl could reach considerably larger sizes in rounds and, when in baroque shapes, could reach up to 25 mm long displaying a solid irregular tail coming from a bulgy body, resembling a fireball, hence the name.
    If you wish to know more on these and other freshwater cultured pearls, join pearl guru Jeremy Shepherd at the Home Gemmology webinar Tuesday, July 28 (2 pm London).
    Check timezone before registering at www.ruigalopim.com/events
    Continue reading
  • Pearls: Forever Fashionable

    Pearls: Forever Fashionable | The South Sea Pearl
    A jewelry store’s pearl counter is a fascinating place. These enchanting gems have represented beauty and perfection ever since man discovered them in ancient times. They have been the subject of countless tales of history, beauty, myth and elegance.

    The Arabian Gulf was the world’s first source of natural pearls and remained so for centuries. Natural pearls from the Gulf are notable for their transparent and high-luster nacre. Together with pearls from the Red Sea and the Strait of Manaar, they have been referred to as “oriental pearls” and are highly valued.

    Part of a pearl’s appeal is its organic origins: It comes from a living animal, a mollusk. And because pearls are slightly porous, they warm up against the skin as they are worn. The wearer and the gems become one.

    The exciting array of pearl choices available today can be overwhelming. When you combine the variety of colors, sizes and shapes with metals and other gemstones in rings, necklaces and earrings, the possible combinations are practically endless.

    So before you set off to buy pearl jewelry, you should understand the basics. Are you looking for natural or cultured pearls? Do you know what to look for in terms of size, luster and color? What price range are you interested in? How are some pearls treated to enhance their appearance? These are all good questions to consider before you begin to shop.

    A retailer who knows the types of natural and cultured pearls that are available and the factors that determine their value will be an invaluable resource to you as you explore pearls.

    In the meantime, here are some basics to get you started.

    Pearls are natural or cultured and grow in mollusks that can live in either saltwater or fresh water. They are made up of layers of calcium carbonate most popularly in the form of nacre, a natural substance produced by pearl oysters that coats the inside of the animal’s shell. This beautiful, lustrous nacre is the very essence of a pearl.

    Natural Saltwater Pearls
    Natural pearls are extremely rare. The Arabian Gulf is the most important source for natural pearls – 70-80 percent of all pearls came from there until the 1950s. The island of Bahrain was a center for trade with northwest India and what is now the modern Middle East. A 4,000-year-old pearl was uncovered in 1989, and excavations at the ancient Bahrain’s Dilmun settlement have confirmed that pearl fishing has been going on for at least 3,000 years.

    Natural saltwater pearls from the Arabian Gulf come from the Pinctada radiata and Pinctada margaritifera. Persian Gulf pearls range in color from white to dark cream and tend to be more yellow than those from the Red Sea and Strait of Manaar, whose characteristic colors are very light yellow, cream and very light pink. The Red Sea also produces some pearls in darker hues that range from intense pink to light to dark violet.

    Natural saltwater pearls are also found occasionally in Baja California, Venezuela, Myanmar, China, Japan, India, French Polynesia, Australia and Africa – the same regions that have cultured pearl industries.

    Saltwater Cultured Pearls
    If you ask someone to describe an Akoya pearl, they will most likely describe a white, round, lustrous gem cultured in Japan and China in Pinctada fucata (martensii). Most akoya cultured pearls are white or cream and some have hints of rosé (pink) or green. The akoya oyster is relatively small, so it doesn’t usually produce a cultured pearl larger than 9 mm. Natural pearls from Pinctada fucata (matensii) are extremely rare.

    Tahitian cultured pearls have only been on the market since the 1970s and come in colors including eggplant purple, peacock green, metallic gray and grayish blue. The mollusk that produces them (Pinctada margaritifera) is native to French Polynesia and is farmed there and in the Cook Islands, Fiji, Australia and New Zealand.

    South Sea cultured pearls come from one of the world’s largest pearl oyster (Pinctada maxima), which produces cultured pearls that can measure 15 mm or larger. They are farmed in Australia, Burma, the Philippines and Indonesia. While South Sea cultured pearls occur in other colors, silver, white and yellow (sometimes referred to as “golden”) are the most common.

    Freshwater Cultured Pearls
    Cultured pearl farmers in China produce the overwhelming majority of cultured freshwater pearls. These cultured pearls vary widely in color and are generally more affordable than saltwater cultured pearls. Sizes are comparable to akoya cultured pearls, with a range between 2 mm and 13 mm, although larger sizes are now available. Fascinating new cultured pearls from fire balls to soufflés have been emerging from China in a dramatic array of colors.

    The chief cultured pearl-producing mussel in the U.S. is the “washboard” M. nervosa. Only a small fraction of the total number of freshwater cultured pearls produced come from the U.S.

    What to look for when picking out pearls
    GIA, the world’s foremost authority on diamonds and gems, created a pearl description system, in order to evaluate the quality of pearls. GIA’s 7 Value Factors include Size, Shape, Color, Luster, Surface, and Nacre. Be sure to ask your sales associate to go through these with you.

    Size: As with other gems, a larger pearl (measured in millimeters) is typically more valuable. The larger the pearl, the more rare and costly it tends to be. But fine quality pearls can be small, and low quality pearls can be large, so a pearl’s ultimate worth depends on how it combines the complete mix of value factors.

    Shape: While round is the most familiar shape, pearls come in a parade of forms (round, near round, oval, button, drop, semi-baroque, baroque). No matter what its shape, if a pearl is or symmetrical, it will be more valuable than one that’s irregular.

    Color: A pearl’s color is a combination of its dominant bodycolor, overtone, the subtle colours that seem to come from within the pearl, and orient, the “play of color” you see when the pearl moves.. Cultured pearls display a broad palette of subtle hues, ranging from warm (yellow, orange and pink) to cool (blue, green and violet).

    Luster: The intensity of light reflected from or just below the surface of the pearl, its luster, contributes the most to the beauty of a pearl. The effect is an inner glow from the heart of the gem. A pearl with excellent luster will look bright and shiny, while one with poor luster is dull and far less valuable. Fine akoyas tend to display a bright, mirror-like gloss. Other pearls tend to feature a softer, satiny luster.

    Surface: A completely clean pearl is a rare treasure. Since rarity influences value, the prices of such pearls run extremely high. The number, nature, and location of surface characteristics (abrasions, bumps, chips, cracks, etc.) can affect the value of any pearl. Numerous or severe surface irregularities – such as chips or gaps – can threaten the durability of the pearl and cause it to break or peel and considerably lower its quality and value. If a surface characteristic is minor and located near a pearl’s drill hole, where it’s less noticeable, it will detract less from the pearl’s appearance and ultimate value.

    Other value factors can minimize the effect of surface characteristics on a pearl’s worth. If the pearl is large and highly lustrous, for example, these pluses can outweigh a slight surface characteristic or two. In fact, excellent luster makes some surface characteristics less noticeable.

    Nacre: Nacre is the very essence of the pearl itself and nacre thickness does affect the value. Quality cultured pearls have ample thickness to allow the pearl to display its beauty.

    Matching: The uniformity of the appearance of pearls in strands and multi-pearl pieces is called matching.

    How to Care for Pearls
    Now that you’ve gotten your pearls, you should know a few things about taking care of them.

    To retain their beauty, they need a certain amount of moisture, which is why you should avoid storing pearls in an airtight or overly dry environment, such as a bank safety deposit box. The human body conveniently provides just the right amount of moisture. Worn often and properly cared for, pearls can look as good in 50 years as they did the day they left the store.

    Pearls are not the most durable of gems. Most everyday items at home and in the office are tougher than pearls, so careless contact can cause damage them over time. Chemicals are the primary threat. Perfume, makeup and hairspray contain ingredients that can eat away the nacre, permanently dulling it. Many cleaning products contain chemicals such as ammonia and chlorine, which can pit gold alloys and quickly damage pearls. Chlorinated swimming pool water is also hazardous. Avoid wearing pearl jewellery when cleaning the house or doing yard work.

    The best way to clean your pearls is with a soft damp cloth, ideally after each time you wear them.

    Are you ready to learn more?
    Consider taking a course to gain a deeper understanding of this fascinating gem. GIA offers an online pearl course in its gemmology eLearning curriculum that you can take from the comfort of your home. It’s a fascinating look at the world of pearls, including their origin, how they get to market, and the GIA 7 Value Factors used to describe their quality. Or, you can choose to take a one-day instructor-led GIA Pearl Grading class where you’ll learn to evaluate the quality of freshwater, South Sea and Tahitian pearls.
    Continue reading
  • FREQUENTLY ASKED QUESTIONS ABOUT AUSTRALIAN SOUTH SEA PEARLS

    FREQUENTLY ASKED QUESTIONS ABOUT AUSTRALIAN SOUTH SEA PEARLS | The South Sea Pearl
    Q:
    What is a pearl made of?
    A pearl is a natural gem created by a living organism. When a foreign object is introduced into a mussel or oyster the animal coats the irritant with a substance called nacre, the same material with which it builds it's shell. Layers of nacre build up to make a pearl.




    Q:
    How much time does it take to complete a strand?
    Strands made of Australian South Sea Pearls up to 15mm are often put together from one harvest. Exceptional strands often take three or more harvests. Some have taken much longer. But the answer is not so simple, because we have been stocking our large pearls for at least the past 10 years to enable us to assemble strands in these sizes. So it is possible that a strand has one pearl from harvest 2004 and another from harvest 1994.

    Q:
    What area in kilometres are the pearl farms spread across?
    The farms are dotted along more than 2,500 kilometres of coastline – from the Cobourg Peninsula to Exmouth on the north-west Australian coast. An equivalent distance to from London to Moscow! This coastline is in the heart of North Australia’s cyclone belt which annually faces the world’s fiercest tropical storms – a management task in itself to ensure the ongoing viability of the pearl project and the safety of the workers who tend the oysters daily throughout the year.

    Q:
    What year was Australia’s first farm (Kuri Bay) established?
    Kuri Bay’s history extends to the post-war resurgence of the pearl coast. This remote settlement was founded in 1956, as Australia’s (and, indeed, the world’s) first South Sea pearl farm.
 Kuri Bay was named for Tokuichi Kuribayashi of Nippo Pearl, the company that provided the technical expertise for this early farming joint venture.

    Q:
    Which order of importance are the 5 virtues of pearl ranked in when pricing a pearl?
    Lustre, Complexion, Shape, Size, Colour.

    Q:
    What size (age) is an oyster before it can be seeded?
    Approximately 3-4 years before the first operation.

    Q:
    What months are seeding and harvest done each year?
    Annually from May to September.

    Q:
    What is the millimetre size of a nucleus?
    It varies depending on the size and health of the oyster. More important is the nacre thickness. Akoya pearls have a nacre thickness of only around 0.1mm, whereas on a 13mm Australian South Sea pearl the average is 2-4mm.

    Q:
    What is a nucleus made of?
    The best nucleus is made from 100 per cent hand-selected Mississippi clam shell. Ongoing research provides unequivocal evidence that the Mississippi clam shell produces the best results, sharing the specific gravity and almost identical composition to the nacre of the Australian South Sea pearl, ensuring an end product of the highest quality and durability. It is common for Chinese Freshwater pearls to use a lower grade material, such as plastic, for the nucleus.

    Q:
    How many people are employed in the Australian pearling industry?
    Approximately 800 employees currently work across the pearl production divisions of the business.

    Q:
    How often are the oysters cleaned?
    Each oyster is cleaned by hand at least once a month – at slightly shorter periods during the Dry season and longer periods during the Wet season.

    Q:
    How many times can an oyster be seeded?
    Generally an oyster is seeded only the one time, occasionally twice and rarely a third time.

    Q:
    How long does it take for a pearl to grow?
    Australian South Sea pearls grow over a 2-3 year period. Other South Sea pearls grow over 1-2 years, and Akoya pearls take only 6 months (on average) to grow.

    Q:
    How big can an oyster grow?
    Bigger than a dinner plate; approximately 50 years of age.

    Q:
    How durable are Australian South Sea pearls?
    The durability of all pearls cannot be described as if all pearls are homogenous; e.g. untreated pearls are much more durable than treated pearls (treatments are processes such as dyeing, bleaching and enhancing lustre by chemical treatment).


    Akoya pearls are generally the most fragile and least durable of all cultured pearls due to their thin coatings of nacre. Akoya pearls are also almost always treated in some way. As a point of reference, an Akoya is deemed to be good quality if its nacre is 0.15mm thick. Good quality Australian South Sea pearls have on average at least 2mm of nacre. The natural pearl nacre of Australian South Sea pearls will respond well to body oils, etc. Being made primarily of calcium carbonate, it is softer than diamonds and will react adversely to acids which destroy calcium carbonate – as would our teeth.

    Q:
    Why are Australian South Sea cultured pearls so rare?
    The world’s jewellery market is dominated by gold, silver, and diamonds, with pearls representing only 2% in value of total jewellery sales. Cultured Australian South Sea pearls account for just 1% in volume of the global production of all cultured pearls, yet they account for nearly a third of the value. This obvious preference for quality has increased the demand for high quality pearls worldwide, thus pearls of a certain quality will remain scarce, as increases in production take years in lead times, and quantities cannot be easily or cheaply increased by alternative sources.

    While natural Australian South Sea pearls are rarely found in the wild today, cultured pearls are virtually indistinguishable from their natural ancestors.


    Q:
    What gives pearls their shape?
    Only Nature can decide what shape and colour a pearl will be. While the small nucleus or seed implanted in a pearl oyster is round in shape, due to the thickness of the South Sea oysters’ nacre, the pearls emerge in a wide range of shapes. Symmetry is rare in nature, and therefore round shapes are the most highly valued. See The Five Virtues for an explanation of the variety of Australian South Sea pearl shapes available.

    Q:
    What is a cultured half pearl?
    Also known as 'mabe' or 'cultured blisters', the cultured half-pearl is initiated by attaching a hemispherical nucleus on the inside lip of the shell. As the oyster grows and secretes its pearl nacre, the half-pearl grows into a domed blister which is later removed from the shell and backed with mother-of-pearl.

    Q:
    What is an Australian South Sea keshi pearl?
    'Keshi' is a Japanese term which relates to 'small' pearls. They can be either natural or cultured. They can have a solid nucleus (such as a grain of sand), a soft nucleus (such as a small piece of organic material), or a hollow centre, but never an implanted nucleus. As they are impossible to differentiate by eye, all keshi pearls are classified as cultured, unless they are examined by x-ray and accompanied by a certificate from a reputable gemmological laboratory. They generally range in size from 2–10 millimetres and remain quite rare.

    Q:
    What gives a pearl its colour?
    The colour of South Sea cultured pearls is determined only by nature and can be any of the colours of the mother-of-pearl oyster in which it forms. The finest Australian South Sea pearl oysters can display a magnificent array of all the colours of the rainbow, and as such, Australian South Sea cultured pearls are found in a myriad of colours from golds though to silvers and, of course, white. Pearls may also have many different coloured overtones, which sometimes combine with a translucent lustre to produce the effect known as orient.

    Q:
    What is a South Sea pearl?
    A South Sea pearl is produced by the Pinctada maxima - the largest of the pearl-producing molluscs. They are mainly produced in Australia, primarily with wild oysters, and in Indonesia and the Philippines with hatchery-reared oysters.

    Continue reading