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Gemmological Association Of Great Britain
The Gemmological Association of Great Britain (Gem-A) is an international gemmology education and qualifications body based in the United Kingdom. History Gem-A dates back to 1908 when a gemmological committee was established by ''The National Association of Goldsmiths''. The aim of the committee was how to best provide the United Kingdom jewellery trade with recognised gemmology qualifications. The recent development of synthetic rubies, synthetic sapphires and cultured pearls had made formal education essential. This committee matured into the Gemmological Association of Great Britain, a Branch of the NAG, and eventually became a wholly independent organisation. Now Gem-A is a registered United Kingdom-based charity and its gemmology and diamond courses are taught in some 25 countries worldwide. Coat of Arms One of the most common symbols used to denote the Association, the Coat of Arms is based upon a design submitted by H. Ellis Tomlinson on behalf of the Association in 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemmology
Gemology or gemmology is the science dealing with natural and artificial gemstone materials. It is a geoscience and a branch of mineralogy. Some jewelers (and many non-jewelers) are academically trained gemologists and are qualified to identify and evaluate gems. History Rudimentary education in gemology for jewellers and gemologists began in the nineteenth century, but the first qualifications were instigated after the National Association of Goldsmiths of Great Britain (NAG) set up a Gemmological Committee for this purpose in 1908. This committee matured into the Gemmological Association of Great Britain (also known as Gem-A), now an educational charity and accredited awarding body with its courses taught worldwide. The first US graduate of Gem-A's diploma course, in 1929, was Robert Shipley, who later established both the Gemological Institute of America and the American Gem Society. There are now several professional schools and associations of gemologists and certificatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. The United Kingdom includes the island of Great Britain, the north-eastern part of the island of Ireland, and many smaller islands within the British Isles. Northern Ireland shares a land border with the Republic of Ireland; otherwise, the United Kingdom is surrounded by the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea and the Irish Sea. The total area of the United Kingdom is , with an estimated 2020 population of more than 67 million people. The United Kingdom has evolved from a series of annexations, unions and separations of constituent countries over several hundred years. The Treaty of Union between the Kingdom of England (which included Wales, annexed in 1542) and the Kingdom of Scotland in 170 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verneuil Process
The Verneuil method (or Verneuil process or Verneuil technique), also called flame fusion, was the first commercially successful method of manufacturing synthetic gemstones, developed in the late 1883 by the French chemist Auguste Verneuil. It is primarily used to produce the ruby, sapphire and padparadscha varieties of corundum, as well as the diamond simulants rutile, strontium titanate and spinel. The principle of the process involves melting a finely powdered substance using an oxyhydrogen flame, and crystallising the melted droplets into a boule. The process is considered to be the founding step of modern industrial crystal growth technology, and remains in wide use to this day. History Since the study of alchemy began, there have been attempts to synthetically produce precious stones, and ruby, being one of the prized cardinal gems, has long been a prime candidate. In the 19th century, significant advances were achieved, with the first ruby formed by melting two sma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sapphire
Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide () with trace amounts of elements such as iron, titanium, chromium, vanadium, or magnesium. The name sapphire is derived via the Latin "sapphirus" from the Greek "sappheiros", which referred to Lapis lazuli, lapis lazuli. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are called ruby, rubies rather than sapphires. Pink-colored corundum may be classified either as ruby or sapphire depending on locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewellery, jewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in large boule (crystal), crystal boules. Because of the remarkable hardness of sapphires 9 on the Mohs scale of mineral hardness, Mohs scale (the third hardest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cultured Pearl
Cultured pearls are formed within a cultured pearl sac with human intervention in the interior of productive living molluscs in a variety of conditions depending upon the mollusc and the goals. Just as the same as natural pearls, cultured pearls can be cultivated in seawater or freshwater bodies. Nowadays, over 95% of the pearls available on the market would be cultured pearls. Development of a pearl A pearl is formed when the mantle tissue is injured by a parasite, an attack of a fish, or another event that damages the external fragile rim of the shell of a mollusk shell bivalve or gastropod. In response, the mantle tissue of the mollusk secretes nacre into the pearl sac, a cyst that forms during the healing process. Chemically speaking, this is calcium carbonate and a fibrous protein called conchiolin. As the nacre builds up in layers of minute aragonite tablets, it fills the growing pearl sac and eventually forms a pearl. Natural pearls are initiated in nature more or l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond
Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the Chemical stability, chemically stable form of carbon at Standard conditions for temperature and pressure, room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest Scratch hardness, hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. They are also the reason that diamond anvil cells can subject materials to pressures found deep in the Earth. Because the arrangement of atoms in diamond is extremely rigid, few types of impurity can contaminate it (two exceptions are boron and nitrogen). Small numbers of lattice defect, defects or impurities (about one per million of lattice atoms) color diamond blue (bor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coat Of Arms
A coat of arms is a heraldry, heraldic communication design, visual design on an escutcheon (heraldry), escutcheon (i.e., shield), surcoat, or tabard (the latter two being outer garments). The coat of arms on an escutcheon forms the central element of the full achievement (heraldry), heraldic achievement, which in its whole consists of a shield, supporters, a crest (heraldry), crest, and a motto. A coat of arms is traditionally unique to an individual person, family, state, organization, school or corporation. The term itself of 'coat of arms' describing in modern times just the heraldic design, originates from the description of the entire medieval chainmail 'surcoat' garment used in combat or preparation for the latter. Roll of arms, Rolls of arms are collections of many coats of arms, and since the early Modern Age centuries, they have been a source of information for public showing and tracing the membership of a nobility, noble family, and therefore its genealogy across tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
King Of Arms
King of Arms is the senior rank of an officer of arms. In many heraldic traditions, only a king of arms has the authority to grant armorial bearings and sometimes certify genealogies and noble titles. In other traditions, the power has been delegated to other officers of similar rank. Heraldic duties In England, the authority to grant a coat of arms is subject to the formal approval of the Earl Marshal in the form of a warrant. In jurisdictions such as the Republic of Ireland the authority to grant armorial bearings has been delegated to a chief herald that serves the same purpose as the traditional king of arms. Canada also has a chief herald, though this officer grants arms on the authority of the Governor General as the Queen's representative through the Herald Chancellor's direct remit. Scotland's only king of arms, the Lord Lyon, exercises the royal prerogative by direct delegation from the Crown and like the Chief Herald of Ireland and the old Ulster King of Arms n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Warrant (law)
A warrant is generally an order that serves as a specific type of authorization, that is, a writ issued by a competent officer, usually a judge or magistrate, that permits an otherwise illegal act that would violate individual rights and affords the person executing the writ protection from damages if the act is performed. A warrant is usually issued by a court and is directed to a sheriff, a constable, or a police officer. Warrants normally issued by a court include search warrants, arrest warrants, and execution warrants. Types * Arrest warrant, issued by a judge to detain someone * Execution warrant, writ issued by a judge authorizing the death of someone * Possessory warrant, a civil writ issued by a judge ordering property delivered to a named person * Search warrant, a writ issued by a judge allowing law enforcement to look inside a property * Warrant of committal, issued by a judge ordering enforcement of a previous order against an uncooperative person or corporation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemstone
A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, and obsidian) and occasionally organic materials that are not minerals (such as amber, jet, and pearl) are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity and notoriety are other characteristics that lend value to gemstones. Apart from jewelry, from earliest antiquity engraved gems and hardstone carvings, such as cups, were major luxury art forms. A gem expert is a gemologist, a gem maker is called a lapidarist or gemcutter; a diamond cutter is called a diamantaire. Characteristics and classification The traditional classification in the West, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnification
Magnification is the process of enlarging the apparent size, not physical size, of something. This enlargement is quantified by a calculated number also called "magnification". When this number is less than one, it refers to a reduction in size, sometimes called ''minification'' or ''de-magnification''. Typically, magnification is related to scaling up visuals or images to be able to see more detail, increasing resolution, using microscope, printing techniques, or digital processing. In all cases, the magnification of the image does not change the perspective of the image. Examples of magnification Some optical instruments provide visual aid by magnifying small or distant subjects. * A magnifying glass, which uses a positive (convex) lens to make things look bigger by allowing the user to hold them closer to their eye. * A telescope, which uses its large objective lens or primary mirror to create an image of a distant object and then allows the user to examine the image clo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearl
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. 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. The ideal pearl is 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 pearl oysters and freshwater mussels make up the majority of those currently sold. Imitation pearls are also widely s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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