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Pearl
A pearl is a hard, glistening object produced within the soft tissue (specifically the mantle (mollusc), mantle) of a living Exoskeleton, shelled mollusk or another animal, such as fossil conulariids. Just like the shell of a mollusk, a pearl is composed of calcium carbonate (mainly aragonite or a mixture of aragonite and calcite) in minute crystalline form, which has deposited in concentric layers. More commercially valuable pearls are perfectly round and smooth, but many other shapes, known as baroque pearls, can occur. The finest quality of natural pearls have been highly valued as gemstones and objects of beauty for many centuries. Because of this, ''pearl'' has become a metaphor for something rare, fine, admirable, and valuable. The most valuable pearls occur spontaneously in the wild but are extremely rare. These wild pearls are referred to as ''natural'' pearls. ''Cultured'' or ''farmed'' pearls from Pinctada, pearl oysters and freshwater mussels make up the majority o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nacre
Nacre ( , ), also known as mother-of-pearl, is an organicinorganic composite material produced by some molluscs as an inner shell layer. It is also the material of which pearls are composed. It is strong, resilient, and iridescent. Nacre is found in some of the most ancient lineages of bivalves, gastropods, and cephalopods. However, the inner layer in the great majority of mollusc shells is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as ''flame structure'' as is found in conch pearls. The outer layer of cultured pearls and the inside layer of pearl oyster and freshwater pearl mussel shells are made of nacre. Other mollusc families that have a nacreous inner shell layer include marine gastropods such as the Haliotidae, the Trochidae and the Turbinidae. Physical characteristics Structure and appearance Nacre is composed of hexagonal platelets, called tablets, of aragonite (a form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridescence
Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear gradually to change colour as the angle of view or the angle of illumination changes. Iridescence is caused by wave interference of light in microstructures or thin films. Examples of iridescence include soap bubbles, feathers, butterfly wings and seashell nacre, and minerals such as opal. Pearlescence is a related effect where some or most of the reflected light is white. The term pearlescent is used to describe certain paint finishes, usually in the automotive industry, which actually produce iridescent effects. Etymology The word ''iridescence'' is derived in part from the Greek word ἶρις ''îris'' ( gen. ἴριδος ''íridos''), meaning ''rainbow'', and is combined with the Latin suffix ''-escent'', meaning "having a tendency toward". Iris in turn derives from the goddess Iris of Greek mythology, who is the personification of the rainbow and acted as a messenger of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalve
Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consisting of a hinged pair of half-bivalve shell, shells known as valve (mollusc), valves. As a group, bivalves have no head and lack some typical molluscan organs such as the radula and the odontophore. Their gills have evolved into ctenidium (mollusc), ctenidia, specialised organs for feeding and breathing. Common bivalves include clams, oysters, Cockle (bivalve), cockles, mussels, scallops, and numerous other family (biology), families that live in saltwater, as well as a number of families that live in freshwater. Majority of the class are benthic filter feeders that bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinctada
''Pinctada'' is a genus of saltwater oysters, marine bivalve mollusks in the family Pteriidae. These pearl oysters have a strong inner shell layer composed of nacre, also known as "mother of pearl". Pearl oysters are not closely related to either the edible oysters of family Ostreidae or the freshwater pearl mussels of the families Unionidae and Margaritiferidae. '' Pinctada margaritifera'' and '' P. maxima'' are used for culturing South Sea and Tahitian pearls. They are cultured widely primarily in the central and eastern Indo-Pacific. A pearl oyster can be seen on the reverse side of the 1,000-peso note of the Philippines. Species of commercial value All species within the genus produce pearls. Attempts have been made to harvest pearls commercially from many ''Pinctada'' species. However, the only species that are currently of significant commercial interest are: * Gulf pearl oyster, ''Pinctada radiata''; Persian Gulf, Red Sea, Mediterranean Sea and throughout the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baroque Pearls
Baroque pearls are pearls with an irregular, non-spherical shape. Shapes can range from minor aberrations to distinctly ovoid, curved, pinched, or lumpy shapes. Most cultured freshwater pearls are baroque because freshwater pearls are mantle-tissue nucleated instead of bead nucleated. Cultured saltwater pearls can also be baroque, but tend to be more teardrop-shaped due to the use of a spherical nucleation bead. Nowadays, most jewelry stores selling baroque pearl jewelry offer cultured freshwater pearls rather than wild freshwater pearls, which are significantly more expensive. Cultured freshwater pearls are affordable and lend themselves well to various pearl jewelry designs. Pearl jewelry stores may bleach or dye freshwater cultured pearls after harvesting to enhance their color. The most valuable baroque pearls are the South Sea and the Tahitian pearls, which are produced by ''Pinctada margaritifera'' (black-lipped oysters) and ''Pinctada maxima'' (gold-lipped and silver-l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imitation Pearl
Imitation pearls are man-made ''faux'' pearls. They are not to be confused with cultured pearls, which are real pearls created through human intervention. Materials used to create imitation pearls include glass, plastic, and mollusc shells. As an alternative, some plastic beads are coated with a pearlescent substance to imitate the natural iridescence of nacre or mother of pearl. Types *Bathed pearl (also called Angel, Sheba, Mikomo, Kobe, Nikko, Sumo, Fijii, Aloha, or "improved cultured pearl") is a mother-of-pearl core coated with a mixture of plastic enamel, lead carbonate, mica, and titanium dioxide, then with a film of iridescent nylon. *Bohemian pearl is a cut and buffed mother-of-pearl protuberance. *Cotton pearl (also called "Utter Ethical pearl") is made merely from cotton and mica. *Glass pearl is a glass bead dipped or sprayed with pearlescent material, or hollow glass bead filled with pearlescent material. One variation is the Majorica pearl. Wax-filled pearl sim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemstone
A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, when cut or polished, is used to make jewellery, jewelry or other adornments. Certain Rock (geology), rocks (such as lapis lazuli, opal, and obsidian) and occasionally organic chemistry, organic materials that are not minerals (such as amber, Jet (gemstone), jet, and pearl) may also be used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some softer minerals such as brazilianite may be used in jewelry because of their color or Lustre (mineralogy), luster or other physical properties that have aesthetic value. However, generally speaking, soft minerals are not typically used as gemstones by virtue of their brittleness and lack of durability. Found all over the world, the industry of coloured gemstones (i.e. anything other than diamonds) is currently estimated at US$1.55billion and is projected to s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margaret
Margaret is a feminine given name, which means "pearl". It is of Latin origin, via Ancient Greek and ultimately from Iranian languages, Old Iranian. It has been an English language, English name since the 11th century, and remained popular throughout the Middle Ages. It became less popular between the 16th and 18th century, but became more common again after this period, becoming the second-most popular female name in the United States in 1903. Since this time, it has become less common, but was still the ninth-most common name for women of all ages in the United States as of the List of most popular given names, 1990 census. Margaret has many diminutive forms in many languages, including Daisy (given name), Daisy, Greta (given name), Greta, Gretchen, Maggie, Madge (given name), Madge, Maisie (given name), Maisie, Marge, Margie, Margo (given name), Margo, Margot, Marnie (given name), Marnie, Meg, Megan, Molly (name), Molly, Peggy (given name), Peggy, and Rita (given name), Rita. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margaritiferidae
Margaritiferidae is a family of medium-sized freshwater mussels, aquatic bivalve molluscs in the order Unionida. Text may have been copied from this source, which is available under Attribution 4.0 International (CC BY 4.0)licence. It is the most threatened of all unionid families. The family is sometimes referred to as the freshwater pearl mussel family, but " freshwater pearl mussel" more often applies to the species ''Margaritifera margaritifera''. The name refers to the thick layer of nacre (mother of pearl) lining the interior of the shell of the species, which enables them to produce pearls. Taxonomy A 2018 study suggested a new phylogeny and systematics of the Margaritiferidae, comprising two subfamilies, Gibbosulinae and Margaritiferinae, and four genera, ''Gibbosula'', ''Cumberlandia'', ''Margaritifera'', and ''Pseudunio''. This family has ancient origins, having diverged from the ancestors of the Unionidae during the Late Triassic with the crown group of the Mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusk
Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The number of additional fossil species is estimated between 60,000 and 100,000, and the proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat, as numerous groups are freshwater and even terrestrial species. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known extant i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Carbonate
Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skeletons and pearls. Materials containing much calcium carbonate or resembling it are described as calcareous. Calcium carbonate is the active ingredient in agricultural lime and is produced when calcium ions in hard water react with carbonate ions to form limescale. It has medical use as a calcium supplement or as an antacid, but excessive consumption can be hazardous and cause hypercalcemia and digestive issues. Chemistry Calcium carbonate shares the typical properties of other carbonates. Notably, it: *reacts with acids, releasing carbonic acid which quickly disintegrates into carbon dioxide and water: : *releases carbon dioxide upon heating, called a thermal decomposition reaction, or calcination (to above 840 °C in the case of ), t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
