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Carroll Chatham
Carroll Chatham (1914–1983) was an American chemist who developed the flux method for synthesizing emeralds. He was the first person to develop a method for creating man-made emeralds that was able to make them commercially available. He founded the jewelry company Chatham which is still selling Chatham emeralds to this day. Early life Carroll Chatham grew up in San Francisco, California and he developed an interest in gemology at an early age. As a teenager, he was already experimenting in his garage. His goal was to synthesize diamonds but after an explosion during one of these attempts, which caused his father to make Chatham change his experiments. This change led him to attempt to synthesize emeralds instead, but this included the challenge of there not being a known method for developing emeralds like the flame fusion method used for creating rubies and sapphires. His first successful experiment was the development of a colorless gem in 1930. This gem was made of beryl, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emerald
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium or sometimes vanadium.Hurlbut, Cornelius S. Jr. and Kammerling, Robert C. (1991) ''Gemology'', John Wiley & Sons, New York, p. 203, . Beryl has a hardness of 7.5–8 on the Mohs scale. Most emeralds are highly included, so their toughness (resistance to breakage) is classified as generally poor. Emerald is a cyclosilicate. Etymology The word "emerald" is derived (via fro, esmeraude and enm, emeraude), from Vulgar Latin: ''esmaralda''/''esmaraldus'', a variant of Latin ''smaragdus'', which was a via grc, σμάραγδος (smáragdos; "green gem") from a Semitic language. According to Webster's Dictionary the term emerald was first used in the 14th century. Properties determining value Emeralds, like all colored gemstones, are graded using four basic parameters–the four ''C''s of connoisseurship: ''color'', ''clarity,'' ''cut'' and ''carat weight''. N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melting Point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at a standard pressure such as 1 atmosphere or 100 kPa. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point or crystallization point. Because of the ability of substances to supercool, the freezing point can easily appear to be below its actual value. When the "characteristic freezing point" of a substance is determined, in fact, the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice, that is, the melting point." Examples For most substances, melting and freezing points are approximately equal. For example, the melting point ''and'' freezing point of mercury is . How ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Place Of Birth Missing
Place may refer to: Geography * Place (United States Census Bureau), defined as any concentration of population ** Census-designated place, a populated area lacking its own municipal government * "Place", a type of street or road name ** Often implies a dead end (street) or cul-de-sac * Place, based on the Cornish word "plas" meaning mansion * Place, a populated place, an area of human settlement ** Incorporated place (see municipal corporation), a populated area with its own municipal government * Location (geography), an area with definite or indefinite boundaries or a portion of space which has a name in an area Placenames * Placé, a commune in Pays de la Loire, Paris, France * Plače, a small settlement in Slovenia * Place (Mysia), a town of ancient Mysia, Anatolia, now in Turkey * Place, New Hampshire, a location in the United States * Place House, a 16th-century mansion largely remodelled in the 19th century, in Fowey, Cornwall * Place House, a 19th-century mansion on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
People From San Francisco
This is a list of notable people from San Francisco, California. It includes people who were born or raised in, lived in, or spent significant portions of their lives in San Francisco, or for whom San Francisco is a significant part of their identity, as well as music groups founded in San Francisco. This list is in order by primary field of notability and then in alphabetical order by last name. Academics * Andrew Smith Hallidie (1836–1900) promoter of the first cable car line, regent of the University of California from 1868 to 1900 * Phoebe Hearst (1842–1919) first woman Regent of the University of California, socialite, philanthropist, feminist and suffragist * Terry Karl (born 1947), professor of Latin American Studies at Stanford University Artists and designers Architects * Edward Charles Bassett (1922–1999) San Francisco based architect, designed many of the buildings in San Francisco with Skidmore, Owings and Merrill. *Vernon DeMars (1908–2005), architect a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1983 Deaths
The year 1983 saw both the official beginning of the Internet and the first mobile cellular telephone call. Events January * January 1 – The migration of the ARPANET to TCP/IP is officially completed (this is considered to be the beginning of the true Internet). * January 24 – Twenty-five members of the Red Brigades are sentenced to life imprisonment for the 1978 murder of Italian politician Aldo Moro. * January 25 ** High-ranking Nazi war criminal Klaus Barbie is arrested in Bolivia. ** IRAS is launched from Vandenberg AFB, to conduct the world's first all-sky infrared survey from space. February * February 2 – Giovanni Vigliotto goes on trial on charges of polygamy involving 105 women. * February 3 – Prime Minister of Australia Malcolm Fraser is granted a double dissolution of both houses of parliament, for elections on March 5, 1983. As Fraser is being granted the dissolution, Bill Hayden resigns as leader of the Australian Labor Party, and in the subsequ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1914 Births
This year saw the beginning of what became known as World War I, after Archduke Franz Ferdinand of Austria, heir to the Austrian throne was assassinated by Serbian nationalist Gavrilo Princip. It also saw the first airline to provide scheduled regular commercial passenger services with heavier-than-air aircraft, with the St. Petersburg–Tampa Airboat Line. Events January * January 1 – The St. Petersburg–Tampa Airboat Line in the United States starts services between St. Petersburg and Tampa, Florida, becoming the first airline to provide scheduled regular commercial passenger services with heavier-than-air aircraft, with Tony Jannus (the first federally-licensed pilot) conveying passengers in a Benoist XIV flying boat. Abram C. Pheil, mayor of St. Petersburg, is the first airline passenger, and over 3,000 people witness the first departure. * January 11 – The Sakurajima volcano in Japan begins to erupt, becoming effusive after a very large earthquake ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wikipedia Student Program
Wikipedia is a multilingual free online encyclopedia written and maintained by a community of volunteers, known as Wikipedians, through open collaboration and using a wiki-based editing system. Wikipedia is the largest and most-read reference work in history. It is consistently one of the 10 most popular websites ranked by Similarweb and formerly Alexa; Wikipedia was ranked the 5th most popular site in the world. It is hosted by the Wikimedia Foundation, an American non-profit organization funded mainly through donations. Wikipedia was launched by Jimmy Wales and Larry Sanger on January 15, 2001. Sanger coined its name as a blend of ''wiki'' and ''encyclopedia''. Wales was influenced by the "spontaneous order" ideas associated with Friedrich Hayek and the Austrian School of economics after being exposed to these ideas by the libertarian economist Mark Thornton. Initially available only in English, versions in other languages were quickly developed. Its combined editions com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seed Crystal
A seed crystal is a small piece of single crystal or polycrystal material from which a large crystal of typically the same material is grown in a laboratory. Used to replicate material, the use of seed crystal to promote growth avoids the otherwise slow randomness of natural crystal growth and allows manufacture on a scale suitable for industry. Crystal enlargement The large crystal can be grown by dipping the seed into a supersaturated solution, into molten material that is then cooled, or by growth on the seed face by passing vapor of the material to be grown over it. Theory The theory behind this effect is thought to derive from the physical intermolecular interaction that occurs between compounds in a supersaturated solution (or possibly vapor). In solution, liberated (soluble) molecules (solute) are free to move about in random flow. This random flow permits for the possibility of two or more molecular compounds to interact. This interaction can potentiate intermolecular fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flux Method
The flux method of crystal growth is a method where the components of the desired substance are dissolved in a solvent (flux). The method is particularly suitable for crystals needing to be free from thermal strain. It takes place in a crucible made of highly stable, non-reactive material. For production of oxide crystals, metals such as platinum, tantalum, and niobium are common. Production of metallic crystals generally uses crucibles made from ceramics such as alumina, zirconia, and boron nitride. The crucibles and their contents are often isolated from the air for reaction, either by sealing them in a quartz ampoule or by using a furnace with atmosphere control. A saturated solution is prepared by keeping the constituents of the desired crystal and the flux at a temperature slightly above the saturation temperature long enough to form a complete solution. Then the crucible is cooled in order to allow the desired material to precipitate. Crystal formation can begin by spontaneou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemology
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] |
Crystal Structure
In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystal, crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric patterns that repeat along the principal directions of Three-dimensional space (mathematics), three-dimensional space in matter. The smallest group of particles in the material that constitutes this repeating pattern is the unit cell of the structure. The unit cell completely reflects the symmetry and structure of the entire crystal, which is built up by repetitive Translation (geometry), translation of the unit cell along its principal axes. The translation vectors define the nodes of the Bravais lattice. The lengths of the principal axes, or edges, of the unit cell and the angles between them are the lattice constants, also called ''lattice parameters'' or ''cell parameters''. The symmetry properties of the crystal are described by the con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
