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Chalmers Topaz
The Chalmer's Topaz is a topaz gem weighing 5,899.5- carats located in Chicago, Illinois' Grainger Hall of Gems, in the Field Museum of Natural History. It was named for former Field Museum trustee William J. Chalmers and his wife Joan Chalmers, who established a fund used to purchase gemstones for the Field Museum collections. The Chalmers Topaz is one of the largest cut topaz gems in the world. See also * List of individual gemstones A number of gemstones have gained fame, either because of their size and beauty or because of the people who owned or wore them. A list of famous gemstones follows. Alexandrites * Smithsonian museums' Alexandrite, the largest cut alexandrite ... References {{reflist Field Museum of Natural History Individual topazes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Topaz
Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al Si O( F, OH). It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden brown to yellow orange. Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple. Although it is often associated with golden yellow and blue, it comes in a variety of colors, including colorless. The rarest are natural pinks, reds, and delicate golden oranges, sometimes with pink hues. Topaz is a nesosilicate mineral. It is one of the hardest naturally occurring minerals and has a relatively low index of refraction. It occurs in many places in the world. Etymology The name "topaz" is usually believed to be derived (via Old French: Topace and Latin: Topazus) from the Greek ''Τοπάζιος'' (Topázios) or ''Τοπάζιον'' (Topázion), from Τοπα ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carat (mass)
The carat (ct) is a unit of mass equal to or 0.00643 troy oz, and is used for measuring gemstones and pearls. The current definition, sometimes known as the metric carat, was adopted in 1907 at the Fourth General Conference on Weights and Measures, and soon afterwards in many countries around the world. The carat is divisible into 100 ''points'' of 2 mg. Other subdivisions, and slightly different mass values, have been used in the past in different locations. In terms of diamonds, a paragon is a flawless stone of at least 100 carats (20 g). The ANSI X.12 EDI standard abbreviation for the carat is CD. Etymology First attested in English in the mid-15th century, the word ''carat'' comes from Italian ''carato'', which comes from Arabic '' qīrāṭ '' قيراط , in turn borrowed from Greek ''kerátion'' κεράτιον 'carob seed', a diminutive of ''keras'' 'horn'. It was a unit of weight, equal to 1/1728 (1/12) of a pound (see Mina (unit)). History Carob seeds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chicago, Illinois
(''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name = United States , subdivision_type1 = State , subdivision_type2 = Counties , subdivision_name1 = Illinois , subdivision_name2 = Cook and DuPage , established_title = Settled , established_date = , established_title2 = Incorporated (city) , established_date2 = , founder = Jean Baptiste Point du Sable , government_type = Mayor–council , governing_body = Chicago City Council , leader_title = Mayor , leader_name = Lori Lightfoot ( D) , leader_title1 = City Clerk , leader_name1 = Anna Valencia ( D) , unit_pref = Imperial , area_footnotes = , area_tot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Museum Of Natural History
The Field Museum of Natural History (FMNH), also known as The Field Museum, is a natural history museum in Chicago, Illinois, and is one of the largest such museums in the world. The museum is popular for the size and quality of its educational and scientific programs, and its extensive scientific-specimen and artifact collections. The permanent exhibitions, which attract up to two million visitors annually, include fossils, current cultures from around the world, and interactive programming demonstrating today's urgent conservation needs. The museum is named in honor of its first major benefactor, Marshall Field, the department-store magnate. The museum and its collections originated from the 1893 World's Columbian Exposition and the artifacts displayed at the fair. The museum maintains a temporary exhibition program of traveling shows as well as in-house produced topical exhibitions. The professional staff maintains collections of over 24 million specimens and objects tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Individual Gemstones
A number of gemstones have gained fame, either because of their size and beauty or because of the people who owned or wore them. A list of famous gemstones follows. Alexandrites * Smithsonian museums' Alexandrite, the largest cut alexandrite weighing 65.08 carats. Aquamarines A birthstone. * The Dom Pedro – The world's largest cut and polished aquamarine. Housed in the permanent collection of the Houston Museum of Natural Science Diamonds :''See List of diamonds'' Emeralds * Bahia Emerald * Carolina Emperor, 310 carats uncut, 64.8 carats cut; discovered in the United States in 2009, resides in the North Carolina Museum of Natural Sciences, Raleigh * Chalk Emerald * Duke of Devonshire Emerald * Emerald of Saint Louis, 51.60 carats cut; discovered in Austria, probably Habachtal, resides in the National Museum of Natural History, Paris * Gachalá Emerald * Mogul Mughal Emerald * Patricia Emerald, 632 carats uncut, dihexagonal (12 sided); discovered in Colombia in 1920, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
