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Marcel Tolkowsky
Marcel Tolkowsky (25 December 1899 – 10 February 1991), Obituary. an engineer by education, was a Belgian member of a Jewish family of diamond cutters from Poland. He is generally acknowledged as the father of the modern round brilliant diamond cut. Many of his family have gone on to become noted diamond cutters, including his cousin Lazare Kaplan and his great-nephew Gabi Tolkowsky. Tolkowsky, as part of his PhD topic at the University of London, systematically studied the grinding of diamonds. Around the same time, in his book ''Diamond Design'', he published the specifications of what would later be called the ''American Standard'' (also known as the ''American Ideal Cut'', ''Tolkowsky cut'', and ''Tolkowsky Brilliant''), which is the diamond-cutting benchmark in North America. It was derived from mathematical calculations that considered both brilliance and fire of the stone. Marcel Tolkowsky found that if a diamond Diamond is a solid form of the element ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid digital subscribers. It also is a producer of popular podcasts such as '' The Daily''. Founded in 1851 by Henry Jarvis Raymond and George Jones, it was initially published by Raymond, Jones & Company. The ''Times'' has won 132 Pulitzer Prizes, the most of any newspaper, and has long been regarded as a national "newspaper of record". For print it is ranked 18th in the world by circulation and 3rd in the U.S. The paper is owned by the New York Times Company, which is publicly traded. It has been governed by the Sulzberger family since 1896, through a dual-class share structure after its shares became publicly traded. A. G. Sulzberger, the paper's publisher and the company's chairman, is the fifth generation of the family to head the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belgium
Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to the southwest, and the North Sea to the northwest. It covers an area of and has a population of more than 11.5 million, making it the 22nd most densely populated country in the world and the 6th most densely populated country in Europe, with a density of . Belgium is part of an area known as the Low Countries, historically a somewhat larger region than the Benelux group of states, as it also included parts of northern France. The capital and largest city is Brussels; other major cities are Antwerp, Ghent, Charleroi, Liège, Bruges, Namur, and Leuven. Belgium is a sovereign state and a federal constitutional monarchy with a parliamentary system. Its institutional organization is complex and is structured on both regional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond Cutting
Diamond cutting is the practice of shaping a diamond from a rough stone into a faceted gem. Cutting diamonds requires specialized knowledge, tools, equipment, and techniques because of its extreme difficulty. The first guild of diamond cutters and polishers (Diamantaire) was formed in 1375 in Nuremberg, Germany, and led to the development of various types of "cut". This has two meanings in relation to diamonds. The first is the shape: square, oval, and so on. The second relates to the specific quality of cut within the shape, and the quality and price will vary greatly based on the cut quality. Since diamonds are one of the hardest materials, special diamond-coated surfaces are used to grind the diamond down. The first major development in diamond cutting came with the "Point Cut" during the later half of the 14th century: the Point Cut follows the natural shape of an octahedral rough diamond crystal, eliminating some waste in the cutting process. Diamond cutting, as well as over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poland
Poland, officially the Republic of Poland, , is a country in Central Europe. Poland is divided into Voivodeships of Poland, sixteen voivodeships and is the fifth most populous member state of the European Union (EU), with over 38 million people, and the List of European countries by area, seventh largest EU country, covering a combined area of . It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordering seven countries. The territory is characterised by a varied landscape, diverse ecosystems, and Temperate climate, temperate transitional climate. The capital and List of cities and towns in Poland, largest city is Warsaw; other major cities include Kraków, Wrocław, Łódź, Poznań, and Gdańsk. Prehistory and protohistory of Poland, Humans have been present on Polish soil since the Lower Paleolithic, with continuous settlement since the end of the Last Glacial Period over 12,000 years ago. Culturally diverse throughout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Round Brilliant
A brilliant is a diamond or other gemstone cut in a particular form with numerous facets so as to have exceptional brilliance. The shape resembles that of a cone and provides maximized light return through the top of the diamond. Even with modern techniques, the cutting and polishing of a diamond crystal always results in a dramatic loss of weight; rarely is it less than 50%. The round brilliant cut is preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal. Oddly shaped crystals such as macles are more likely to be cut in a '' fancy cut''—that is, a cut other than the round brilliant—which the particular crystal shape lends itself to. Facet proportions and names The original round brilliant-cut was developed by Marcel Tolkowsky in 1919. The ideal proportions are 100% diameter, 53% table, 43.1% pavilion and 16.2% crown. The girdle and culet (if anynot part of Tolkowsky's original design) are cut from the ideal brillian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond Cut
A diamond cut is a style or design guide used when shaping a diamond for polishing such as the brilliant cut. Cut does not refer to shape (pear, oval), but the symmetry, proportioning and polish of a diamond. The cut of a diamond greatly affects a diamond's brilliance; this means if it is cut poorly, it will be less luminous. In order to best use a diamond gemstone's material properties, a number of different diamond cuts have been developed. A diamond cut constitutes a more or less symmetrical arrangement of facets, which together modify the shape and appearance of a diamond crystal. Diamond cutters must consider several factors, such as the shape and size of the crystal, when choosing a cut. The practical history of diamond cuts can be traced back to the Middle Ages, while their theoretical basis was not developed until the turn of the 20th century. Design, creation and innovation continue to the present day: new technology—notably laser cutting and computer-aided design ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lazare Kaplan International
Lazare Kaplan International Inc. (LKI) is a diamond manufacturing and distribution company based in New York City. The Chairman of the Board of Directors is Maurice Tempelsman. The first LKI was located in Ponce, Puerto Rico, at , a community named after the factory was located there. LKI was founded in 1903 where it operated until it was moved to Caguas, Puerto Rico in the 1970s. Business activities LKI's main business activity is cutting and polishing "ideal-cut" and "fine make" diamonds, which it sells to upscale retail jewelers throughout the world. Some of these diamonds are distributed loose while others are set in jewelry under the ''Lazare Diamond'' brand. LKI distributes its products through over 1,500 retail partners and customers in 29 countries. Although primarily based in the United States, LKI also has sales offices in Belgium, Japan, China and Hong Kong. LKI has operated in Japan since 1973, Southeast Asia since 1987 and Latin America since 1997. LKI's first fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gabi Tolkowsky
Gabriel S. "Gabi" Tolkowsky (born January 1, 1939) Clara Chow, ''Urban, The Straits Times'', 31 October 2008 known for cutting the famous , is one of the world's most renowned ters. Known as the father of the modern diamond cut. and the great nephew of |
Diamond
Diamond is a 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 chemically stable form of carbon at room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest 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 defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (defects), green (radiation exposure), purple, pink, orange, or red. Diamond also has a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the west and south by the Pacific Ocean. Because it is on the North American Plate, North American Tectonic Plate, Greenland is included as a part of North America geographically. North America covers an area of about , about 16.5% of Earth's land area and about 4.8% of its total surface. North America is the third-largest continent by area, following Asia and Africa, and the list of continents and continental subregions by population, fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 579 million people in List of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's population. In Americas (terminology)#Human ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemological Institute Of America
The Gemological Institute of America (GIA) is a nonprofit institute based in Carlsbad, California. It is dedicated to research and education in the field of gemology and the jewelry arts. Founded in 1931, GIA's mission is to protect buyers and sellers of gemstones by setting and maintaining the standards used to evaluate gemstone quality. The institute does so through research, gem identification and diamond grading services and a variety of educational programs. Through its library and subject experts, GIA acts as a resource of gem and jewelry information for the trade, the public and media outlets. In 1953 the GIA developed its International Diamond Grading System and the "four Cs" ( cut, clarity, color, and carat weight) as a standard to compare and evaluate the quality of diamonds. Today, the institute is headquartered in Carlsbad, California and operates in 13 countries, with 11 campuses, 9 laboratories and 4 research centers. History The story of the GIA begins in the 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1899 Births
Events January 1899 * January 1 ** Spanish rule ends in Cuba, concluding 400 years of the Spanish Empire in the Americas. ** Queens and Staten Island become administratively part of New York City. * January 2 – **Bolivia sets up a customs office in Puerto Alonso, leading to the Brazilian settlers there to declare the Republic of Acre in a revolt against Bolivian authorities. **The first part of the Jakarta Kota–Anyer Kidul railway on the island of Java is opened between Batavia Zuid ( Jakarta Kota) and Tangerang. * January 3 – Hungarian Prime Minister Dezső Bánffy fights an inconclusive duel with his bitter enemy in parliament, Horánszky Nándor. * January 4 – **U.S. President William McKinley's declaration of December 21, 1898, proclaiming a policy of benevolent assimilation of the Philippines as a United States territory, is announced in Manila by the U.S. commander, General Elwell Otis, and angers independence activists who had fought a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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