How Do You Know if a Clam Has a Pearl

Hard object produced within a living shelled mollusc

Pearl
Various pearls
General
Category	Carbonate mineral, poly peptide
Formula (repeating unit of measurement)	Calcium carbonate, CaCO3 Conchiolin
Strunz classification	05.eight
Crystal organization	Orthorhombic[1]
Identification
Color	white, pink, silver, foam, dark-brown, greenish, blue, black, yellowish, orangish, red, aureate, majestic, iridescent
Cleavage	None[i]
Fracture	Uneven, various
Mohs scale hardness	two.5–4.5[1]
Streak	white
Specific gravity	two.60–2.85[1]
Refractive index	Common pearl: 1.52-ane.66 Black pearl: 1.53-1.69[1]
Birefringence	0.156
Pleochroism	Absent-minded
Dispersion	None
Ultraviolet fluorescence	White pearls: low-cal blue to light xanthous; Yellow and aureate pearls: yellow-green, light-green brown to nighttime brownish; Black pearls: commonly pinkish to orange-reddish[2]

Georgian seed pearl gold band

A pearl is a hard, glistening object produced within the soft tissue (specifically the mantle) of a living shelled mollusk or another animal, such as fossil conulariids. Simply similar the beat of a mollusk, a pearl is equanimous of calcium carbonate (mainly aragonite or a mixture of aragonite and calcite)^[iii] in minute crystalline form, which has deposited in concentric layers. The ideal pearl is perfectly round and smoothen, but many other shapes, known every bit bizarre pearls, can occur. The finest quality of natural pearls have been highly valued as gemstones and objects of beauty for many centuries. Considering of this, pearl has become a metaphor for something rare, fine, admirable and valuable.

The most valuable pearls occur spontaneously in the wild, merely are extremely rare. These wild pearls are referred to as natural pearls. Cultured or farmed pearls from pearl oysters and freshwater mussels make up the majority of those currently sold. Fake pearls are besides widely sold in inexpensive jewelry, but the quality of their iridescence is usually very poor and is easily distinguished from that of genuine pearls. Pearls take been harvested and cultivated primarily for use in jewelry, but in the by were besides used to beautify clothing. They have also been crushed and used in cosmetics, medicines and pigment formulations.

Whether wild or cultured, jewel-quality pearls are almost always nacreous and iridescent, like the interior of the beat that produces them. However, most all species of shelled mollusks are capable of producing pearls (technically "calcareous concretions") of bottom shine or less spherical shape. Although these may besides be legitimately referred to as "pearls" past gemological labs and besides under U.Due south. Federal Trade Commission rules,^[four] and are formed in the same way, most of them accept no value except as curiosities.

Etymology [edit]

The English word pearl comes from the French perle, originally from the Latin perna meaning leg, later the ham- or mutton leg-shaped bivalve.^[five]

The scientific name for the family of pearl-bearing oysters, Margaritiferidae comes from the Old Persian discussion for pearl *margārīta- which is the source of the English language name Margaret.^{[six] [seven] [8]}

Definition [edit]

A blackness pearl and a beat of the black-lipped pearl oyster. The iridescent colors originate from nacre layers.

All shelled mollusks can, past natural processes, produce some kind of "pearl" when an irritating microscopic object becomes trapped within its mantle folds, but the great majority of these "pearls" are not valued as gemstones. Nacreous pearls, the best-known and most commercially meaning, are primarily produced by two groups of molluskan bivalves or clams. A nacreous pearl is made from layers of nacre, by the aforementioned living process as is used in the secretion of the mother of pearl which lines the trounce.

Natural (or wild) pearls, formed without human intervention, are very rare. Many hundreds of pearl oysters or mussels must exist gathered and opened, and thus killed, to find even ane wild pearl; for many centuries, this was the only way pearls were obtained, and why pearls fetched such extraordinary prices in the past. Cultured pearls are formed in pearl farms, using human being intervention as well as natural processes.

Ane family unit of nacreous pearl bivalves – the pearl oyster – lives in the sea, while the other – a very different grouping of bivalves – lives in freshwater; these are the river mussels such equally the freshwater pearl mussel. Saltwater pearls can abound in several species of marine pearl oysters in the family unit Pteriidae. Freshwater pearls grow within certain (merely past no means all) species of freshwater mussels in the order Unionida, the families Unionidae and Margaritiferidae.

Concrete backdrop [edit]

Electron microscopy image of a fractured surface of nacre

The unique luster of pearls depends upon the reflection, refraction, and diffraction of light from the translucent layers. The thinner and more numerous the layers in the pearl, the effectively the luster. The iridescence that pearls display is caused by the overlapping of successive layers, which breaks up light falling on the surface. In addition, pearls (especially cultured freshwater pearls) can be dyed yellow, green, blueish, brown, pinkish, purple, or black. The very best pearls have a metal mirror-like luster.

Because pearls are made primarily of calcium carbonate, they tin can exist dissolved in vinegar. Calcium carbonate is susceptible to fifty-fifty a weak acid solution considering the crystals react with the acerb acid in the vinegar to class calcium acetate and carbon dioxide.

Freshwater and saltwater pearls [edit]

Freshwater and saltwater pearls may sometimes look quite similar, but they come up from different sources.

Freshwater pearls class in various species of freshwater mussels, family Unionidae, which live in lakes, rivers, ponds and other bodies of fresh water. These freshwater pearl mussels occur not only in hotter climates, but besides in colder more temperate areas such as Scotland (where they are protected under law). About freshwater cultured pearls sold today come from China.

Saltwater pearls grow within pearl oysters, family Pteriidae, which live in oceans. Saltwater pearl oysters are normally cultivated in protected lagoons or volcanic atolls.

Cosmos [edit]

Formation of non–bead-cultured Akoya "keshi" pearls produced in a P. i. fucata mollusk. (A) Optical overview of a nonbeaded keshi–cultured pearl. (B) Cross-section showing CaCO3 growth begins onto an organic eye. (C) Mature nacre. (D and E) Atomic-resolution image of atoms in nacre. (F) Transition from spherulitic aragonite structures to nacre. (G and H) Aggregated nanoparticles form massive aragonite. (I) Formation of nacre begins directly on massive aragonite. CC-license, PNAS 2021 118 (42); https://doi.org/10.1073/pnas.2107477118

The mollusk'southward curtain (protective membrane) deposits layers of calcium carbonate (CaCO₃) in the form of the mineral aragonite or a mixture of aragonite and calcite (polymorphs with the same chemical formula, but dissimilar crystal structures) held together past an organic horn-like compound called conchiolin. The combination of aragonite and conchiolin is called nacre, which makes up mother-of-pearl. The ordinarily held belief that a grain of sand acts as the irritant is in fact rarely the case. Typical stimuli include organic material, parasites, or even damage that displaces mantle tissue to some other role of the clam'south body. These small particles or organisms gain entry when the shell valves are open for feeding or respiration. In cultured pearls, the irritant is typically an introduced piece of the mantle epithelium, with or without a spherical bead (beaded or beadless cultured pearls).^{[9] [10]}

Natural pearls [edit]

Natural pearls are near 100% calcium carbonate and conchiolin. It is idea that natural pearls form under a fix of accidental conditions when a microscopic intruder or parasite enters a bivalve clam and settles inside the shell. The mollusk, irritated by the intruder, forms a pearl sac of external mantle tissue cells and secretes the calcium carbonate and conchiolin to embrace the irritant. This secretion process is repeated many times, thus producing a pearl. Natural pearls come in many shapes, with perfectly circular ones being comparatively rare.

Typically, the build-upward of a natural pearl consists of a brown central zone formed past columnar calcium carbonate (usually calcite, sometimes columnar aragonite) and a yellow to white outer zone consisting of nacre (tabular aragonite). In a pearl cantankerous-section such as the diagram, these two dissimilar materials tin can be seen. The presence of columnar calcium carbonate rich in organic textile indicates juvenile mantle tissue that formed during the early on phase of pearl development. Displaced living cells with a well-defined task may continue to perform their function in their new location, often resulting in a cyst. Such displacement may occur via an injury. The frail rim of the shell is exposed and is decumbent to damage and injury. Crabs, other predators and parasites such every bit worm larvae may produce traumatic attacks and cause injuries in which some external drape tissue cells are disconnected from their layer. Embedded in the conjunctive tissue of the mantle, these cells may survive and form a modest pocket in which they continue to secrete calcium carbonate, their natural product. The pocket is chosen a pearl sac, and grows with fourth dimension by cell division. The juvenile pall tissue cells, according to their stage of growth, secrete columnar calcium carbonate from pearl sac'southward inner surface. In time, the pearl sac's external drape cells keep to the germination of tabular aragonite. When the transition to nacre secretion occurs, the brown pebble becomes covered with a nacreous coating. During this process, the pearl sac seems to travel into the shell; however, the sac actually stays in its original relative position the mantle tissue while the shell itself grows. Afterwards a couple of years, a pearl forms and the vanquish may exist found by a lucky pearl fisher.^[11]

Cultured pearls [edit]

Cultured pearls are the response of the shell to a tissue implant. A tiny piece of mantle tissue (called a graft) from a donor shell is transplanted into a recipient vanquish, causing a pearl sac to form into which the tissue precipitates calcium carbonate. At that place are a number of methods for producing cultured pearls: using freshwater or seawater shells, transplanting the graft into the drapery or into the gonad, and adding a spherical dewdrop equally a nucleus. Most saltwater cultured pearls are grown with beads. Trade names of cultured pearls are Akoya ( 阿古屋 ), white or golden South bounding main, and blackness Tahitian. Most beadless cultured pearls are curtain-grown in freshwater shells in Communist china, and are known as freshwater cultured pearls.

Cultured pearls tin be distinguished from natural pearls by X-ray examination.^[12] Nucleated cultured pearls are frequently 'preformed' every bit they tend to follow the shape of the implanted crush bead nucleus. Later on a bead is inserted into the oyster, it secretes a few layers of nacre around the dewdrop; the resulting cultured pearl can so be harvested in equally few every bit twelve to eighteen months.

When a cultured pearl with a bead nucleus is X-rayed, it reveals a unlike structure to that of a natural pearl (see diagram). A beaded cultured pearl shows a solid center with no concentric growth rings, whereas a natural pearl shows a series of concentric growth rings. A beadless cultured pearl (whether of freshwater or saltwater origin) may show growth rings, only also a complex cardinal cavity, witness of the first precipitation of the immature pearl sac.^[12]

Fake pearls [edit]

Some imitation pearls (also called shell pearls) are but fabricated of mother-of-pearl, coral or conch shell, while others are made from drinking glass and are coated with a solution containing fish scales called essence d'Orient. Although imitation pearls look the part, they exercise non have the same weight or smoothness as real pearls, and their luster will also dim profoundly.

Gemological identification [edit]

A well-equipped gem testing laboratory tin can distinguish natural pearls from cultured pearls by using gemological X-ray equipment to examine the middle of a pearl. With X-rays it is possible to see the growth rings of the pearl, where the layers of calcium carbonate are separated by sparse layers of conchiolin. The differentiation of natural pearls from not-beaded cultured pearls can be very hard without the use of this Ten-ray technique.

Natural and cultured pearls can exist distinguished from faux pearls using a microscope. Another method of testing for imitations is to rub ii pearls against each other. Imitation pearls are completely smoothen, simply natural and cultured pearls are equanimous of nacre platelets, making both experience slightly gritty.

Value of a natural pearl [edit]

Pearl tiara of Empress Eugénie (1853) featuring 212 natural pearls, Louvre, Paris.

Fine quality natural pearls are very rare jewels. Their values are determined similarly to those of other precious gems, according to size, shape, colour, quality of surface, orient and luster.

Unmarried natural pearls are oftentimes sold every bit collectors' items, or set as centerpieces in unique jewelry. Very few matched strands of natural pearls be, and those that do oftentimes sell for hundreds of thousands of dollars. (In 1917, jeweler Pierre Cartier purchased the Fifth Avenue mansion that is now the New York Cartier store in substitution for a matched double strand of natural pearls Cartier had been collecting for years; at the time, it was valued at US$1 million.)^[xiii]

The introduction and advance of the cultured pearl hitting the pearl manufacture hard. Pearl dealers publicly disputed the actuality of these new cultured products, and left many consumers uneasy and confused about their much lower prices. Essentially, the controversy damaged the images of both natural and cultured pearls. By the 1950s, when a significant number of women in developed countries could afford their ain cultured pearl necklace, natural pearls were reduced to a small, sectional niche in the pearl manufacture.

Origin of a natural pearl [edit]

Previously, natural pearls were found in many parts of the earth. Present day natural pearling is confined by and large to seas off Bahrain. Commonwealth of australia also has one of the world's last remaining fleets of pearl diving ships. Australian pearl divers dive for south ocean pearl oysters to be used in the cultured south bounding main pearl industry. The catch of pearl oysters is similar to the numbers of oysters taken during the natural pearl days. Hence significant numbers of natural pearls are yet constitute in the Australian Indian Ocean waters from wild oysters. Ten-ray examination is required to positively verify natural pearls found today.

Types of cultured pearls [edit]

A blister pearl, a half-sphere, formed flush confronting the shell of the pearl oyster.

A keshi pearl is a pearl equanimous entirely of nacre and results from mishaps in the culturing process. About are quite small, typically only a few millimeters in diameter, and are often irregular in shape. In seeding a cultured pearl, a slice of mantle muscle from a sacrificed oyster is placed with a dewdrop of mother of pearl within a host oyster. If the slice of curtain should slip off the bead, a keshi pearl forms of baroque shape about the mantle piece. Therefore, while a keshi pearl could be considered superior to cultured pearls with a female parent of pearl bead center, in the cultured pearl industry the oyster's resources used to create a mistaken all-nacre baroque pearl is a bleed on the product of the intended round cultured pearl. Therefore, the pearl manufacture is making ongoing attempts to improve culturing technique and so that keshi pearls do not occur. All-nacre pearls may i solar day exist limited to natural found pearls.^{[14] [fifteen] [16]} Today many "keshi" pearls are really intentional, with post-harvest shells returned to the water to regenerate a pearl in the existing pearl sac.

Tahitian pearls, oftentimes referred to as black pearls,^[17] are highly valued because of their rarity; the culturing process for them dictates a smaller volume output and they can never be mass-produced considering, in common with most bounding main pearls, the oyster can only be nucleated with one pearl at a time, while freshwater mussels are capable of multiple pearl implants. Before the days of cultured pearls, black pearls were rare and highly valued for the simple reason that white pearl oysters rarely produced naturally black pearls, and blackness pearl oysters rarely produced whatever natural pearls at all.

Since the development of pearl culture technology, the black pearl oysters Pinctada margaritifera found in Tahiti and many other Pacific islands including the Melt Islands and Fiji are being extensively used for producing cultured pearls. The rarity of the black cultured pearl is now a "comparative" issue. The black cultured pearl is rare when compared to Chinese freshwater cultured pearls, and Japanese and Chinese akoya cultured pearls, and is more valuable than these pearls. However, it is more arable than the Southward Sea pearl, which is more valuable than the black cultured pearl. This is just because the black pearl oyster Pinctada margaritifera is far more abundant than the elusive, rare, and larger due south sea pearl oyster Pinctada maxima, which cannot be institute in lagoons, only which must be dived for in a rare number of deep ocean habitats or grown in hatcheries.

Blackness pearls are very rarely black: they are usually shades of green, purple, aubergine, blueish, grey, silver or peacock (a mix of several shades, like a peacock's feather).^{[ commendation needed ]}

Black cultured pearls from the blackness pearl oyster – Pinctada margaritifera – are not Southward Sea pearls, although they are often mistakenly described equally black South Sea pearls. In the absence of an official definition for the pearl from the black all use to, these pearls are usually referred to as "black pearls".^{[ commendation needed ]}

The correct definition of a S Sea pearl – as described past CIBJO and GIA – is a pearl produced by the Pinctada maxima ^[18] pearl oyster. South Sea pearls are the color of their host Pinctada maxima oyster – and tin be white, silverish, pink, gold, cream, and any combination of these basic colors, including overtones of the various colors of the rainbow displayed in the pearl nacre of the oyster vanquish itself.

South Sea pearls are the largest and rarest of the cultured pearls – making them the about valuable.^{[19] [20]} Prized for their exquisitely beautiful 'orient' or lustre, South Sea pearls are now farmed in diverse parts of the world where the Pinctada maxima oysters can be constitute, with the finest South Ocean pearls being produced by Paspaley along the remote coastline of Northward-Western Commonwealth of australia.^{[twenty] [21]} White and silver colored Due south Sea pearls tend to come up from the Broome expanse of Commonwealth of australia, while aureate colored ones are more prevalent in the Philippines and Indonesia.

A subcontract in the Gulf of California, Mexico, is culturing pearls from the black lipped Pinctada mazatlanica oysters and the rainbow lipped Pteria sterna oysters.^[22] Also called Concha Nácar, the pearls from these rainbow lipped oysters fluoresce red under ultraviolet low-cal.

From other species [edit]

A trounce of the Indian volute, Melo melo, surrounded by a number of pearls from this species

Biologically speaking, under the right prepare of circumstances, nearly any shelled mollusk can produce some kind of pearl. However, most of these molluskan pearls have no luster or iridescence. The great bulk of mollusk species produce pearls which are not bonny, and are sometimes not even very durable. Such pearls usually have no value at all, except perchance to a scientist or collector, or as a curiosity. These objects used to exist referred to equally "calcareous concretions" by some gemologists, even though a malacologist would still consider them to exist pearls. Valueless pearls of this type are sometimes establish in edible mussels, edible oysters, escargot snails, and so on. The GIA and CIBJO now only use the term 'pearl' (or, where appropriate, the more descriptive term 'non-nacreous pearl') when referring to such items^{[23] [24]} and, under Federal Trade Commission rules, various mollusk pearls may be referred to as 'pearls', without qualification.^[4]

A few species produce pearls that can exist of interest every bit gemstones. These species include the bailer shell Melo, the behemothic clam Tridacna, various scallop species, Pen shells Pinna, and the Haliotis iris species of abalone. Pearls of abalone, or paua, are mabe pearls, or cicatrice pearls, unique to New Zealand waters and are commonly referred to as 'blue pearls'. They are admired for their incredible luster and naturally bright vibrant colors that are often compared to opal. Another case is the conch pearl (sometimes referred to simply as the 'pink pearl'), which is institute very rarely growing betwixt the pall and the shell of the queen conch or pink conch, Strombus gigas, a large sea snail or marine gastropod from the Caribbean Sea. These pearls, which are often pink in color, are a by-product of the conch fishing industry, and the all-time of them display a shimmering optical result related to chatoyance known as 'flame structure'.

Somewhat similar gastropod pearls, this time more orangish in hue, are (again very rarely) found in the horse conch Triplofusus papillosus.

The 2d largest pearl known was plant in the Philippines in 1934 and is known as the Pearl of Lao Tzu. It is a naturally occurring, non-nacreous, calcareous concretion (pearl) from a giant mollusk. Because it did not grow in a pearl oyster information technology is not pearly; instead the surface is glossy similar porcelain. Other pearls from behemothic clams are known to exist, just this is a especially large one weighing fourteen lb (half dozen.4 kg).

The largest known pearl (also from a behemothic mollusk) is the Pearl of Puerto, as well plant in the Philippines past a fisherman from Puerto Princesa, Palawan Island. The enormous pearl is thirty cm wide (1 ft), 67 cm long (2.2 ft) and weighs 75 lb (34 kg).^[25]

History [edit]

Pearl hunting [edit]

A 14th-century piece of vesture used by Kuwaiti defined searching for pearls in the Persian Gulf

The ancient relate Mahavamsa mentions the thriving pearl industry in the port of Oruwella in the Gulf of Mannar in Sri Lanka. It also records that eight varieties of pearls accompanied Prince Vijaya's embassy to the Pandyan male monarch too equally king Devanampiya Tissa's embassy to Emperor Ashoka.^{[26] [27]} Pliny the Elder (23–79AD) praised the pearl fishery of the Gulf as most productive in the globe.^{[28] [29] [30]}

For thousands of years, seawater pearls were retrieved by defined in the Indian Ocean in areas such equally the Persian Gulf, the Red Sea and the Gulf of Mannar.^{[31] [32] [33]} Evidence also suggest a prehistoric origin to pearl diving in these regions.^{[32] [33]} Starting in the Han Dynasty (206 BC–220 Advertising), the Chinese hunted extensively for seawater pearls in the South Red china Bounding main.^[34] Tanka pearl divers of 12th century China attached ropes to their waists in lodge to exist safely brought back up to the surface.^[35]

When Spanish conquistadors arrived in the Western Hemisphere, they discovered that around the islands of Cubagua and Margarita, some 200 km north of the Venezuelan coast, was an all-encompassing pearl bed (a bed of pearl oysters). One discovered and named pearl, La Peregrina pearl, was offered to Philip Two of Spain who intended to give it as a gift for his girl on the occasion of her matrimony, but the Male monarch found it so beautiful that he kept it for himself. Afterwards, he elevated information technology to exist part of the Castilian Crown Jewel. and from so on the pearl is recorded in every royal inventory for more than 200 years. According to Garcilasso de la Vega, who says that he saw La Peregrina at Seville in 1607,^[36] this was establish at Panama in 1560 past a slave worker who was rewarded with his freedom, and his possessor with the office of alcalde of Panama.

Margarita pearls are extremely hard to detect today and are known for their unique yellow colour. Earlier the beginning of the 20th century, pearl hunting was the about common way of harvesting pearls. Defined manually pulled oysters from ocean floors and river bottoms and checked them individually for pearls. Not all mussels and oysters produce pearls. In a booty of 3 tons, merely three or four oysters volition produce perfect pearls.^{[ citation needed ]}

British Isles [edit]

Pearls were one of the attractions which drew Julius Caesar to Britain.^[37] They are, for the near function, freshwater pearls from mussels. Pearling was banned in the U.1000. in 1998 due to the endangered status of river mussels.^[38] Discovery and publicity about the sale for a substantial sum of the Abernethy pearl in the River Tay had resulted in heavy exploitation of mussel colonies during the 1970s and 80s by weekend warriors.^[39] When it was permitted information technology was carried on mainly by Scottish Travellers^[40] who found pearls varied from river to river with the River Oykel in the Highlands being noted for the finest rose-pinkish pearls.^[41] In that location are ii firms in Scotland that are licensed to sell pre-1998 freshwater pearls.^[42]

Pearl farming [edit]

A pearl existence extracted from an akoya pearl oyster.

Today, the cultured pearls on the market can be divided into ii categories. The first category covers the beaded cultured pearls, including akoya, South Sea and Tahiti. These pearls are gonad grown, and normally one pearl is grown at a time. This limits the number of pearls at a harvest period. The pearls are commonly harvested after 1 yr for akoya, 2–4 years for Tahitian and S Sea, and 2–7 years for freshwater. This perliculture process was outset developed by the British biologist William Saville-Kent who passed the information along to Tatsuhei Mise and Tokichi Nishikawa from Japan. The second category includes the non-beaded freshwater cultured pearls, like the Biwa or Chinese pearls. As they grow in the mantle, where on each wing up to 25 grafts tin can be implanted, these pearls are much more frequent and saturate the market completely. An impressive comeback in quality has taken place over x years when the former rice-grain-shaped pebbles are compared with the nigh circular pearls of today. Later, large near perfect round bead nucleated pearls up to 15mm in diameter have been produced with metallic luster.

The nucleus bead in a beaded cultured pearl is generally a polished sphere made from freshwater mussel shell. Along with a minor piece of mantle tissue from another mollusk (donor shell) to serve as a catalyst for the pearl sac, information technology is surgically implanted into the gonad (reproductive organ) of a saltwater clam. In freshwater perliculture, only the piece of tissue is used in most cases, and is inserted into the fleshy mantle of the host mussel. South Sea and Tahitian pearl oysters, besides known equally Pinctada maxima and Pinctada margaritifera, which survive the subsequent surgery to remove the finished pearl, are oft implanted with a new, larger beads as part of the same procedure and and then returned to the h2o for another ii–3 years of growth.

Despite the common misperception, Mikimoto did not notice the process of pearl civilization. The accepted process of pearl civilization was developed past the British Biologist William Saville-Kent in Australia and brought to Japan by Tokichi Nishikawa and Tatsuhei Mise. Nishikawa was granted the patent in 1916, and married the daughter of Mikimoto. Mikimoto was able to use Nishikawa'southward technology. After the patent was granted in 1916, the technology was immediately commercially applied to akoya pearl oysters in Japan in 1916. Mise'south blood brother was the showtime to produce a commercial crop of pearls in the akoya oyster. Mitsubishi's Baron Iwasaki immediately practical the technology to the south bounding main pearl oyster in 1917 in the Philippines, and later in Buton, and Palau. Mitsubishi was the kickoff to produce a cultured south bounding main pearl – although it was non until 1928 that the first pocket-sized commercial crop of pearls was successfully produced.

The original Japanese cultured pearls, known as akoya pearls, are produced past a species of small pearl oyster, Pinctada fucata martensii, which is no bigger than 6 to 8 cm (ii.four to 3.1 in) in size, hence akoya pearls larger than ten mm in diameter are extremely rare and highly priced. Today, a hybrid mollusk is used in both Nihon and Red china in the production of akoya pearls.

Cultured Pearls were sold in cans for the export market. These were packed in Japan past the I.C.P. Canning Factory (International Pearl Company 50.T.D.) in Nagasaki Pref. Nippon.^{[ citation needed ]}

Timeline of pearl production [edit]

Mitsubishi commenced pearl civilization with the S Sea pearl oyster in 1916, as soon every bit the applied science patent was commercialized. Past 1931 this projection was showing signs of success, but was upset by the death of Tatsuhei Mise. Although the project was recommenced later Tatsuhei'due south death, the project was discontinued at the beginning of WWII before pregnant productions of pearls were achieved.

After WWII, new south sea pearl projects were commenced in the early 1950s at Kuri Bay and Port Essington in Commonwealth of australia, and Burma. Japanese companies were involved in all projects using technicians from the original Mitsubishi South Body of water pre-state of war projects. Kuri Bay is now the location of ane of the largest and most well-known pearl farms owned by Paspaley, the biggest producer of South Sea pearls in the world.^[43]

In 2010, Mainland china overtook Japan in akoya pearl production.^[44] Nippon has all but ceased its production of akoya pearls smaller than 8 mm.^[44] Japan maintains its condition as a pearl processing middle, however, and imports the majority of Chinese akoya pearl production. These pearls are then processed (oft but matched and sorted), relabeled as product of Japan, and exported.^[45]

In the past 2 decades, cultured pearls take been produced using larger oysters in the south Pacific and Indian Ocean. The largest pearl oyster is the Pinctada maxima, which is roughly the size of a dinner plate. South Sea pearls are characterized by their large size and warm luster. Sizes up to 14 mm in diameter are not uncommon. In 2013, Indonesia Pearl^[46] supplied 43 pct of Due south Sea Pearls international market.^[47] The other significant producers are Commonwealth of australia, Philippines, Myanmar and Malaysia.^[48]

Freshwater pearl farming [edit]

In 1914, pearl farmers began growing cultured freshwater pearls using the pearl mussels native to Lake Biwa. This lake, the largest and most ancient in Japan, lies near the city of Kyoto. The extensive and successful use of the Biwa Pearl Mussel is reflected in the name Biwa pearls, a phrase which was at one time nearly synonymous with freshwater pearls in general. Since the time of tiptop production in 1971, when Biwa pearl farmers produced six tons of cultured pearls, pollution has acquired the virtual extinction of the industry. Japanese pearl farmers recently^{[ when? ]} cultured a hybrid pearl mussel – a cross between Biwa Pearl Mussels and a closely related species from China, Hyriopsis cumingi, in Lake Kasumigaura. This manufacture has as well nearly ceased production, due to pollution. Currently, the Belpearl company based out of Kobe, Japan continues to buy the remaining Kasumiga-ura pearls.

Japanese pearl producers also invested in producing cultured pearls with freshwater mussels in the region of Shanghai, Mainland china. Communist china has since get the globe'due south largest producer of freshwater pearls, producing more than 1,500 metric tons per twelvemonth (in addition to metric measurements, Japanese units of measurement such as the kan and momme are sometimes encountered in the pearl industry).

Led by pearl pioneer John Latendresse and his wife Chessy, the United States began farming cultured freshwater pearls in the mid-1960s. National Geographic magazine introduced the American cultured pearl as a commercial product in their August 1985 issue. The Tennessee pearl farm has emerged every bit a tourist destination in contempo years, but commercial production of freshwater pearls has ceased.

Momme weight [edit]

For many cultured pearl dealers and wholesalers, the preferred weight measure used for loose pearls and pearl strands is the momme. Momme is a weight measure used by the Japanese for centuries. Today, momme weight is yet the standard unit of measurement of measure used by most pearl dealers to communicate with pearl producers and wholesalers. 1 momme corresponds to i/1000 kan. Reluctant to give upward tradition, the Japanese government formalized the kan measure in 1891 equally being exactly 3.75 kilograms or viii.28 pounds. Hence, i momme = 3.75 grams or 3750 milligrams.

In the United States, during the 19th and 20th centuries, through trade with Japan in silk fabric the momme became a unit of measurement indicating the quality of silk fabric.

Though millimeter size range is typically the first factor in determining a cultured pearl necklace's value, the momme weight of pearl necklace volition allow the buyer to chop-chop determine if the necklace is properly proportioned. This is especially true when comparing the larger south sea and Tahitian pearl necklaces.

In jewelry [edit]

The value of the pearls in jewelry is determined by a combination of the luster, color, size, lack of surface flaw and symmetry that are appropriate for the type of pearl under consideration. Amid those attributes, luster is the most of import differentiator of pearl quality according to jewelers.

All factors existence equal, however, the larger the pearl the more valuable it is. Large, perfectly circular pearls are rare and highly valued. Teardrop-shaped pearls are ofttimes used in pendants.

Gallery [edit]

• 

  A necklace of white pearls

• 

  George Villiers, 1st Duke of Buckingham wearing white pearls

• 

  Queen of Italy, Margherita of Savoy, owned one of the virtually famous collections of natural pearls. She is wearing a multi-strand choker and a rope of pearls

• 

  Pearl bracelet from the 1840s

• 

  Pearl earrings

• 

  "Pearl Trader" painting on mica in 1870 Republic of india

Shapes [edit]

Pearls are mostly of spherical shapes. Perfectly round pearls are the rarest and most valuable shape. Semi-rounds are as well used in necklaces or in pieces where the shape of the pearl tin be bearded to look similar it is a perfectly round pearl. Button pearls are like a slightly flattened round pearl and can also brand a necklace, but are more than frequently used in single pendants or earrings where the back half of the pearl is covered, making information technology look like a larger, rounder pearl.

Pear-shaped pearls sometimes look similar teardrop pearls and are most often seen in earrings, pendants, or as a centre pearl in a necklace. Baroque pearls have a dissimilar appeal; they are often highly irregular with unique and interesting shapes. They are also commonly seen in necklaces. Circled pearls are characterized by concentric ridges, or rings, around the torso of the pearl.

In general, cultured pearls are less valuable than natural pearls, whereas imitation pearls have almost no value. One way that jewelers can determine whether a pearl is cultured or natural is to take a gemlab perform an X-ray examination of the pearl. If 10-rays reveals a nucleus, the pearl is probable a bead-nucleated saltwater pearl. If no nucleus is present, but irregular and small dark inner spots indicating a cavity are visible, combined with concentric rings of organic substance, the pearl is likely a cultured freshwater. Cultured freshwater pearls can often exist confused for natural pearls which present every bit homogeneous pictures which continuously darken toward the surface of the pearl. Natural pearls will often show larger cavities where organic affair has dried out and decomposed.

Lengths of pearl necklaces [edit]

There is a special vocabulary used to describe the length of pearl necklaces. While most other necklaces are only referred to by their concrete measurement, pearl necklaces are named by how low they hang when worn effectually the neck. A collar, measuring 10 to xiii inches or 25 to 33 cm in length, sits directly against the throat and does non hang downward the cervix at all; collars are often made up of multiple strands of pearls. Pearl chokers, measuring 14 to 16 inches or 35 to 41 cm in length, nestle just at the base of the neck. A strand called a princess length, measuring 17 to 19 inches or 43 to 48 cm in length, comes downward to or only below the collarbone. A matinee length, measuring 20 to 24 inches or 50 to threescore cm in length, falls just above the breasts. An opera length, measuring 28 to 35 inches or lxx to 90 cm in length, will be long plenty to reach the breastbone or sternum of the wearer; and longer still, a pearl rope, measuring more than 45 inches or 115 cm in length, is whatever length that falls down farther than an opera.

Necklaces tin also be classified as uniform, or graduated. In a uniform strand of pearls, all pearls are classified as the same size, but actually fall in a range. A compatible strand of akoya pearls, for case, volition mensurate within 0.5 mm. So a strand will never exist 7 mm, but volition be 6.5–7 mm. Freshwater pearls, Tahitian pearls, and South Sea pearls all mensurate to a full millimeter when considered uniform.

A graduated strand of pearls almost ofttimes has at least 3 mm of differentiation from the ends to the centre of the necklace. Popularized in the The states during the 1950s past the GIs bringing strands of cultured akoya pearls home from Nippon, a three.5 momme, 3 mm to 7 mm graduated strand was much more affordable than a uniform strand because most of the pearls were small.

Colors [edit]

Earrings and necklaces can also be classified on the grade of the color of the pearl: saltwater and freshwater pearls come in many different colors. While white, and more than recently black, saltwater pearls are by far the almost pop, other color tints tin be found on pearls from the oceans. Pink, blue, champagne, green, and even purple saltwater pearls can exist encountered, but to collect enough of these rare colors to form a complete string of the aforementioned size and same shade can take years.

The vast majority of cheap colored pearls have been subjected to some form of dye, oftentimes a fabric dye. This dye will but tend to penetrate the start layer or two of nacre, but this is enough to impart vivid and sometimes garish color to otherwise white pearls. Truly valuable pearls are never dyed, and this process is not believed to add and in most cases would but subtract from their market place value.

Religious references [edit]

Hindu scriptures [edit]

The Hindu tradition describes the sacred Nine Pearls which were first documented in the Garuda Purana, one of the books of the Hindu scriptures. Ayurveda contains references to pearl pulverisation as a stimulant of digestion and to treat mental ailments. Co-ordinate to Marco Polo, the kings of Malabar wore a necklace of 108 rubies and pearls which was given from one generation of kings to the adjacent. The reason was that every male monarch had to say 108 prayers every morning time and every evening.^[49] At least until the outset of the 20th century information technology was a Hindu custom to present a completely new, undrilled pearl and pierce it during the wedding ceremony.^[50]

The Pearl, which can be transliterated to "Moti", a type of "Mani" from Sanskrit, is also associated with many Hindu deities, the well-nigh famous being the Kaustubha that Lord Vishnu wears on his chest.

Hebrew scriptures [edit]

The Hebrew word פְּנִינִים 'pearl(southward)' appears in several places in the Hebrew Bible (Chore 28:xviii; Proverbs iii:15; eight:xi; 20:15; 31:ten; Lamentations four:7), although its etymology is unclear.^[51]

New Testament scriptures [edit]

Religious pendant showing Christ blessing, framed with rubies and pearls, from the Byzantine empire, 12th or 13th century

In a Christian New Testament parable (Matthew 13:45–46), Jesus compared the Kingdom of Heaven to a "pearl of great cost". "Once more, the kingdom of heaven is like unto a merchant homo, seeking goodly (fine) pearls: Who, when he had plant one pearl of smashing price, went and sold all that he had, and bought it."

The twelve gates of the New Jerusalem are reportedly each made of a single pearl in Revelation 21:21, that is, the Pearly Gates. "And the twelve gates were twelve pearls: every several gate was of i pearl: and the street of the city was pure gold, as it were transparent glass."

Holy things are compared to pearls in Matthew vii:half dozen: "Give not that which is holy unto the dogs, neither bandage ye your pearls before swine, lest they trample them under their feet, and turn again and rend y'all."

Pearls are also found in numerous references showing the wickedness and pride of a people, every bit in Revelation 18:xvi. "And maxim, Alas, alas, that neat city, that was clothed in fine linen, in purple, and cherry-red, and decked with gold, and precious stones, and pearls!"

Islamic scriptures [edit]

The Quran often mentions that dwellers of paradise will be adorned with pearls:

22:23 God will admit those who believe and work righteous deeds, to Gardens beneath which rivers flow: they shall be adorned therein with bracelets of gold and pearls; and their garments there volition exist of silk.

35:33 Gardens of Eternity will they enter: therein will they be adorned with bracelets of gilt, silver and pearls; and their garments there will be of silk.

52:24 Round nearly them will serve, [devoted] to them, youths [handsome] as pearls well-guarded.

Additional references [edit]

The metaphor of a pearl appears in the longer Hymn of the Pearl, a verse form respected for its loftier literary quality, and use of layered theological metaphor, found inside one of the texts of Gnosticism.

The Pearl of Groovy Toll is a book of scripture in The Church of Jesus Christ of Latter-mean solar day Saints (LDS Church) and some other Latter Day Saint denominations.

See also [edit]

• Ammolite – some other organic gemstone formed primarily of fossil aragonite mollusk shells
• Bahrain Pearling Trail, a UNESCO Globe Heritage Site in Muharraq, Bahrain
• Broome, Western Commonwealth of australia, a pearling town
• Cave pearl
• La Pelegrina pearl
• Les pêcheurs de perles, The Pearl Fishers, an opera by Georges Bizet
• Oriental Pride
• Pearl Maxima, one of the largest nacreous pearls always found
• Pearl of Lao Tzu
• Pearl of Kuwait
• Pearl of Puerto, largest pearl in the world
• Pearl powder, used in Traditional Chinese Medicine
• The Pearl (novella), a novella past John Steinbeck

References [edit]

1. ^ ^{a b c d e} Schumann, Walter (2001). Gemstones of the World. Robert Hale. p. 230. ISBN978-0-7198-0301-7.
2. ^ Lazzarelli, Herve Nicolas (2010). Blue Chart Gem Identification. p. 8. Archived from the original on October half dozen, 2017.
3. ^ "Pearl". Gemdat.org. Archived from the original on April 4, 2017. Retrieved April three, 2017.
4. ^ ^{a b} "Guides for the Jewelry, Precious Metals, and Pewter Industries". Ftc.gov. May 30, 1996. Archived from the original on May 28, 2010. Retrieved July 17, 2010.
5. ^ Shorter Oxford English language Dictionary (6th ed.), Oxford University Press, 2007, ISBN978-0-19-920687-2
6. ^ "Margaret". Behind the Proper noun. Retrieved August 25, 2020.
7. ^ "Margaret". Online Etymology Lexicon. Retrieved August 25, 2020.
8. ^ "مروارید". Wiktionary. Retrieved Baronial 25, 2020.
9. ^ Neil H. Landman, et al. (2001) Pearls: A Natural History, Harry Abrams, Inc., ISBN 0-8109-4495-2
10. ^ "Pearl oyster farming and pearl culture". Fao.org. Archived from the original on March xx, 2008. Retrieved May 17, 2013.
11. ^ Kenneth Scarratt, The Pearl and the Dragon, Houlton; 1st edition (1999) ISBN 0-935681-07-eight
12. ^ ^{a b} Farn, Alexander Eastward. (2013). Pearls : Natural, Cultured and Imitation. Burlington: Elsevier Scientific discipline. pp. ninety–108. ISBN9781483162737.
13. ^ Strack, Elisabeth. "Pearls". Ruhle-Diebener-Verlag, 2006, p. 38 ISBN 3981084802.
14. ^ The Pearl Book, pp. 47–49, 4th edition, Matlins, Antoinette, Gemstone Printing, copyright 2008
15. ^ The Pearl Story, Gemstone Chance Series, volume 2, copyright 2007 America'due south Collectibles Network,
16. ^ Hanni, H A (June 2006). "Keshi Perlen: Ein Erklarungbedurftiger Begriff (Keshi Pearls: a term in need of explanation)". Zeitschrift der Deutschen Gemmologischen Gesellschaft. DGemG. 55 (one–ii): 39–50.
17. ^ Pouvreau, Stéphane; et al. (2000). "Ecophysiological model of growth and reproduction of the black pearl oyster, Pinctada margaritifera: potential applications for pearl farming in French Polynesia" (PDF). Aquaculture. 186 (i–2): 117–144. doi:10.1016/S0044-8486(99)00373-7.
18. ^ Pinctada maxima Archived August xx, 2017, at the Wayback Automobile. MissJoaquim.com Retrieved on May 31, 2017.
19. ^ How To Buy Pearls Archived September 28, 2013, at the Wayback Car. Nature.berkeley.edu. Retrieved on Oct 14, 2015.
20. ^ ^{a b} Scarratt, Kenneth (2012). "Natural Pearls from Australian Pinctada maxima". Gems & Gemology. 48 (4): 236–261. doi:10.5741/GEMS.48.iv.236. S2CID 130970595.
21. ^ "Gem of the South Sea" (PDF). Archived (PDF) from the original on September 30, 2013.
22. ^ Concha Nacar | The Ocean of Cortez Pearl Blog Archived February 25, 2014, at the Wayback Machine. Perlas.com.mx (November 22, 2010). Retrieved on 2015-ten-14.
23. ^ "CIBJO 'Pearl Book'" (PDF). Archived from the original (PDF) on July 23, 2011. Retrieved July 30, 2010.
24. ^ "GIA 'Gems & Gemology' magazine news annal". Gia.edu. Archived from the original on Jan 13, 2009. Retrieved July thirty, 2010.
25. ^ "Fisherman hands in behemothic pearl he kept under the bed for 10 years". The Guardian. Archived from the original on August 24, 2016. Retrieved August 25, 2016.
26. ^ Senaveratna, John M (1930). The story of the Sinhalese: From the almost ancient times up to the cease of "The Mahavasna", or great dynasty; Vijaya to Maha Sena (B.C. 543 to A.D. 302). W.1000.A. Wahid. pp. 16–9, 46, 130, 144–viii, 161–3, 213. ISBN9788120612716. Archived from the original on Dec twenty, 2017.
27. ^ Kunz, George F.; Stevenson, Charles (1908). The volume of the pearl. New York: The Century Co. p. two.
28. ^ R. Raghu Prasad and P. V. Ramachandran Nair (1973). "India and the Indian Ocean Fisheries" (PDF). Journal of the Marine Biological Clan of India. 15: 1–19. Archived (PDF) from the original on July 18, 2011.
29. ^ Arnold Wright (1999). Twentieth century impressions of Ceylon: its history, people, commerce, industries, and resource. p. 227. ISBN978-81-206-1335-v. Archived from the original on January eighteen, 2017.
30. ^ James Hornell (2009). The Indian Pearl Fisheries of the Gulf of Manar and Palk Bay. BiblioBazaar. p. 6. ISBN978-1-110-87096-7. Archived from the original on Jan 18, 2017.
31. ^ De Silva, Thousand. Chiliad. (1995). Book ii of History of Ceylon, History of Ceylon: History of Sri Lanka. Peradeniya: Ceylon University Printing. p. 56. ISBN978-955-589-004-5. OCLC 952216.
32. ^ ^{a b} "History of the Discovery and Appreciation of Pearls - the Organic Gem Perfected by Nature". internetstones.com. Archived from the original on December 6, 2015. Retrieved January 31, 2016.
33. ^ ^{a b} ROBERT CARTER (2005). "THE HISTORY AND PREHISTORY OF PEARLING IN THE Farsi GULF" (PDF). Archived (PDF) from the original on May 13, 2016. Retrieved January 31, 2016.
34. ^ Bycroft, Michael (2019). Gems in the Early on Modern Earth: Materials, Knowledge and Global Trade, 1450-1800. Switzerland: Palgrave Macmillan. p. 124. ISBN9783319963792.
35. ^ Needham, Joseph (1971). Science and Civilisation in Cathay. Cambridge Academy Press. p. 672. ISBN9780521070607.
36. ^ Garcilasso, "Historie des Incas, Rois du Perou," Amsterdam, 1704, Vol. Two, P. 352.
37. ^ "It was not merely Britain'southward mineral resources or her pretty slaves that had persuaded Caesar to brand his military move across the Channel that summer: according to his biographer Gaius Suetonius Tranquillus information technology was something quite different. It was her pearls." Finlay, Victoria. Jewels: A Cloak-and-dagger History (Kindle Locations 1264-1267). Random House Publishing Group. Kindle Edition.
38. ^ "Unlike sea pearls, which come from oysters, freshwater pearls come up from mussels. And although farmed mussels are common throughout the world, wild colonies are now so endangered that in 1998 pearling was forbidden in the U.k. river system. Finlay, Victoria. Jewels: A Secret History (Kindle Locations 1289-1290). Random House Publishing Group. Kindle Edition.
39. ^ "The new weekend pearl-fishers were "by and large heart-anile men driving large cars with beer coolers in the back" and they would spend afternoons pulling hundreds of live mussels out of the rivers, opening them, and throwing away the shells, with non a care for conservation or the breeding season. All they cared about was finding another Abernethy pearl. Finlay, Victoria. Jewels: A Secret History (Kindle Locations 1375-1377). Random Business firm Publishing Group. Kindle Edition.
40. ^ "Pearlers were mostly Highland traveling people..." Finlay, Victoria. Jewels: A Secret History (Kindle Location 1296). Random Business firm Publishing Group. Kindle Edition.
41. ^ "Pearls from the Oykel River, northwest of Inverness, for example, are a sweet rose pink, and have ever been the most valuable." Finlay, Victoria. Jewels: A Secret History (Kindle Location 1341). Random Business firm Publishing Grouping. Kindle Edition.
42. ^ Scottish Freshwater Pearls Archived January 20, 2018, at the Wayback Machine accessed January 19, 2018
43. ^ Travel more. Create better memories (May 19, 2011). "Welcome to Kuri Bay Paspaley Pearl Farm". Ytravelblog.com. Archived from the original on September 27, 2013. Retrieved September 26, 2013.
44. ^ ^{a b} Pearl Guide: comparison Nippon – Prc akoya production Archived September 2, 2011, at the Wayback Machine. pearl-guide.com
45. ^ Ward, Fred (2002) Pearls (Fred Ward Gem Book), third Edition, Gem Guides Book Company, pp. 35–36, ISBN ane-887651-08-Ten
46. ^ "Special Virtues Indonesian Southward Ocean Pearls". February 24, 2018. Archived from the original on Baronial 20, 2017.
47. ^ "Indonesian Pearls Figures". February 24, 2018. Archived from the original on Baronial 20, 2017.
48. ^ "Indonesia Pasok 43 Persen Mutiara Dunia". August 13, 2013. Archived from the original on Feb 21, 2014.
49. ^ Kunz, George F.; Stevenson, Charles (1908). The book of the pearl. New York: The Century Co. p. 412.
50. ^ Kunz, George F.; Stevenson, Charles (1908). The volume of the pearl. New York: The Century Co. p. 350.
51. ^ Noonan, Benjamin J. (Oct 29, 2019). Non-Semitic Loanwords in the Hebrew Bible. doi:10.1515/9781646020416. ISBN9781646020416. S2CID 242580641.

External links [edit]

• The History of Pearls. PBS Pearl History Special.

bartongerentow.blogspot.com

Source: https://en.wikipedia.org/wiki/Pearl

Share this post