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Caldasite
Caldasite (, , ) is a rare uraniferous ore of zirconium found in the Poços de Caldas massif, located in the states of Minas Gerais and São Paulo, Brazil. It is most often found as a dark gray, very dense, hard rock. It also appears as a friable brown substance. The massif is an alkaline complex, formed by a large intrusion during the mid-Cretaceous. The ore is a result of hydrothermal alteration of the nepheline-syenitic rocks; it has also been weathered ''Weathered'' is the third studio album by American rock band Creed, released on November 20, 2001. It was the last Creed album to be released until '' Full Circle'' came out in October 2009, with Creed disbanding in June 2004. It is the only Cr ... out and concentrated in paleoplacer deposits. References Further reading * * * * * * * * * * * * {{cite book , last1=Ulbrich , first1=H.H.G.J. , last2=Vlach , first2=S.R.F. , last3=Demaiffe , first3=D. , last4=Ulbrich , first4=M.N.C. , chapter=Structure and orig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poços De Caldas
Poços de Caldas is a municipality in the south of Minas Gerais state, Brazil, in the microregion of the same name. Its estimated population in 2020 was 168,641 inhabitants. The city is known for its hot springs. History Poços was founded in 1872. The region had been inhabited by the Cataguases Indians, who were expelled from their lands by the '' Bandeiras Unidas Paulistas'' during their quest for gold. The place was first called ''Freguesia de Nossa Senhora da Saúde das Águas de Caldas'' ("Parish of Our Lady of Health of Caldas Waters"). In 1874 it became a district, then, in 1875, it was elevated to the category of city. It became famous after the discovery of the hot springs, and many important people began to visit the spa in search of cures provided by the water. The name comes from Caldas da Rainha, a spa town in central Portugal. Geography It lies on the boundary of the state of São Paulo at 1186 meters elevation and is the main socio-economic nucleus of its regi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zircon
Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of the range of substitution in zircon is (Zr1–y, REEy)(SiO4)1–x(OH)4x–y. Zircon precipitates from silicate melts and has relatively high concentrations of high field strength incompatible elements. For example, hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green. The name derives from the Persian ''zargun'', meaning "gold-hued". This word is corrupted into "jargoon", a term applied to light-colored zircons. The English word "zircon" is derived from ''Zirkon'', which is the German adaptation of this word. Yellow, orange, and red zircon is also known as "hyacinth", ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baddeleyite
Baddeleyite is a rare zirconium oxide mineral (ZrO2 or zirconia), occurring in a variety of monoclinic prismatic crystal forms. It is transparent to translucent, has high indices of refraction, and ranges from colorless to yellow, green, and dark brown. See etymology below. Baddeleyite is a refractory mineral, with a melting point of 2700 °C. Hafnium is a substituting ''impurity'' and may be present in quantities ranging from 0.1 to several percent. It can be found in igneous rocks containing potassium feldspar and plagioclase. Baddeleyite is commonly not found with zircon (ZrSiO4), because it forms in silica-undersaturated rocks, such as mafic rocks. This is because, when silica is free in the system (silica-saturated/oversaturated), zircon is the dominating phase, not baddeleyite. It belongs to the monoclinic-prismatic class, of the P21/c crystal system. It has been used for geochronology. Geologic occurrence Baddeleyite was first found in Sri Lanka in 1892. It can b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all isotopes of uranium are unstable; the half-lives of its naturally occurring isotopes range between 159,200 years and 4.5 billion years. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead, and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite. In nature, uranium is found as uranium-238 (99. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triuranium Octoxide
Triuranium octoxide (U3O8) is a compound of uranium. It is present as an olive green to black, odorless solid. It is one of the more popular forms of yellowcake and is shipped between mills and refineries in this form. U3O8 has potential long-term stability in a geologic environment. In the presence of oxygen (O2), uranium dioxide (UO2) is oxidized to U3O8, whereas uranium trioxide (UO3) loses oxygen at temperatures above 500 °C and is reduced to U3O8. The compound can be produced by any one of three primary chemical conversion processes, involving either uranium tetrafluoride (UF4) or uranyl fluoride (UO2F2) as intermediates. It is generally considered to be the more attractive form for disposal purposes because, under normal environmental conditions, U3O8 is one of the most kinetically and thermodynamically stable forms of uranium. Its particle density is 8.3 g cm−3. Triuranium octoxide is converted to uranium hexafluoride for the purpose of uranium enrichment. Solid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all isotopes of uranium are unstable; the half-lives of its naturally occurring isotopes range between 159,200 years and 4.5 billion years. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead, and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite. In nature, uranium is found as uranium-238 (99. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zirconium
Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'', "gold-like" or "as gold"). It is a lustrous, grey-white, strong transition metal that closely resembles hafnium and, to a lesser extent, titanium. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Zirconium forms a variety of inorganic and organometallic compounds such as zirconium dioxide and zirconocene dichloride, respectively. Five isotopes occur naturally, four of which are stable. Zirconium compounds have no known biological role. Characteristics Zirconium is a lustrous, greyish-white, soft, ductile, malleable metal that is solid at room temperature, though it is hard and brittle at lesser purities. In powder form, zirconium is highl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Massif
In geology, a massif ( or ) is a section of a planet's crust that is demarcated by faults or flexures. In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole. The term also refers to a group of mountains formed by such a structure. In mountaineering and climbing literature, a massif is frequently used to denote the main mass of an individual mountain. The massif is a smaller structural unit of the crust than a tectonic plate, and is considered the fourth-largest driving force in geomorphology. The word is taken from French (in which the word also means "massive"), where it is used to refer a large mountain mass or compact group of connected mountains forming an independent portion of a range. One of the most notable European examples of a massif is the Massif Central of the Auvergne region of France. The Face on Mars is an example of an extraterrestrial massif. Massifs may also form underwater, as with the Atlanti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minas Gerais
Minas Gerais () is a state in Southeastern Brazil. It ranks as the second most populous, the third by gross domestic product (GDP), and the fourth largest by area in the country. The state's capital and largest city, Belo Horizonte (literally "Beautiful Horizon"), is a major urban and finance center in Latin America, and the sixth largest municipality in Brazil, after the cities of São Paulo, Rio de Janeiro, Salvador, Brasília and Fortaleza, but its metropolitan area is the third largest in Brazil with just over 5.8 million inhabitants, after those of São Paulo and Rio de Janeiro. Nine Brazilian presidents were born in Minas Gerais, the most of any state. The state has 10.1% of the Brazilian population and is responsible for 8.7% of the Brazilian GDP. With an area of —larger than Metropolitan France—it is the fourth most extensive state in Brazil. The main producer of coffee and milk in the country, Minas Gerais is known for its heritage of architecture and colonia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
São Paulo (state)
São Paulo () is one of the Federative units of Brazil, 26 states of the Brazil, Federative Republic of Brazil and is named after Paul of Tarsus, Saint Paul of Tarsus. A major industrial complex, the state has 21.9% of the Brazilian population and is responsible for 33.9% of Brazil's GDP. São Paulo also has the List of Brazilian federative units by Human Development Index, second-highest Human Development Index (HDI) and GDP per capita, the List of Brazilian states by infant mortality, fourth-lowest infant mortality rate, the List of Brazilian states by life expectancy, third-highest life expectancy, and the List of Brazilian states by literacy rate, third-lowest rate of illiteracy among the federative units of Brazil. São Paulo alone is wealthier than Argentina, Uruguay, Paraguay, and Bolivia combined. São Paulo is also the world's twenty-eighth-most populous Administrative division, sub-national entity and the most populous sub-national entity in the Americas. With more than 4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area and the seventh most populous. Its capital is Brasília, and its most populous city is São Paulo. The federation is composed of the union of the 26 States of Brazil, states and the Federal District (Brazil), Federal District. It is the largest country to have Portuguese language, Portuguese as an List of territorial entities where Portuguese is an official language, official language and the only one in the Americas; one of the most Multiculturalism, multicultural and ethnically diverse nations, due to over a century of mass Immigration to Brazil, immigration from around the world; and the most populous Catholic Church by country, Roman Catholic-majority country. Bounded by the Atlantic Ocean on the east, Brazil has a Coastline of Brazi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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