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Capgaronnite
Capgaronnite (•) is a mineral that forms small tufted aggregates or isolated crystals with a maximum width of 0.02mm and a maximum length of 0.1mm. This mineral is related to perroudite in chemical composition and crystal structure. Capgaronnite is associated with secondary minerals of Cu like olivenite, cyanotrichite, and tennantite. Occurrence Capgaronnite is a rare mineral that was observed in the Cap-Garonne copper-lead mine of Var, France. Capgaronnite is found in cavities of Triassic Conglomerate (geology) and Sandstone. Chemical properties The Chemical composition of capgaronnite was determined by Electron probe microanalysis of capgaronnite. This analysis technique uses an electron beam to bombard a sample and recording the resultant x-rays for wavelengths know to each element. Chemical analysis of capgaronnite is very difficult, because of the volatility of the elements. Silver in particular is very mobile and capgaronnite crystals, on average, are very small. The f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfide Mineral
The sulfide minerals are a class of minerals containing sulfide (S2−) or disulfide (S22−) as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, the sulfarsenides and the sulfosalts.http://www.minerals.net/mineral/sort-met.hod/group/sulfgrp.htm Minerals.net Dana Classification, SulfidesKlein, Cornelis and Cornelius S. Hurlbut, Jr., 1986, ''Manual of Mineralogy'', Wiley, 20th ed., pp 269-293 Sulfide minerals are inorganic compounds. Minerals Common or important examples include: * Acanthite * Chalcocite * Bornite * Galena *Sphalerite * Chalcopyrite * Pyrrhotite * Millerite * Pentlandite * Covellite *Cinnabar * Realgar * Orpiment * Stibnite * Pyrite * Marcasite * Molybdenite Sulfarsenides: * Cobaltite * Arsenopyrite * Gersdorffite Sulfosalts: * Pyrargyrite * Proustite * Tetrahedrite * Tennantite * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the chief terrestrial vertebrates during this time. A specialized subgroup of arch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east and the Pacific Ocean to the west. Chile covers an area of , with a population of 17.5 million as of 2017. It shares land borders with Peru to the north, Bolivia to the north-east, Argentina to the east, and the Drake Passage in the far south. Chile also controls the Pacific islands of Juan Fernández, Isla Salas y Gómez, Desventuradas, and Easter Island in Oceania. It also claims about of Antarctica under the Chilean Antarctic Territory. The country's capital and largest city is Santiago, and its national language is Spanish. Spain conquered and colonized the region in the mid-16th century, replacing Inca rule, but failing to conquer the independent Mapuche who inhabited what is now south-central Chile. In 1818, after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Museum Of Natural History (France)
The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7.1 million visitors, it was the eighteenth most visited museum in the world and the second most visited natural history museum in the world after the Natural History Museum in London."The World's most popular museums", CNN.com, 22 June 2017. Opened in 1910, the museum on the National Mall was one of the first Smithsonian buildings constructed exclusively to hold the national collections and research facilities. The main building has an overall area of with of exhibition and public space and houses over 1,000 employees. The museum's collections contain over 145 million specimens of plants, animals, fossils, minerals, rocks, meteorites, human remains, and human cultural artifacts, the largest natural history collection in the world. It i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Centre For Diffraction Data
The International Centre for Diffraction Data (ICDD) maintains a database of powder diffraction patterns, the Powder Diffraction File (PDF), including the d-spacings (related to angle of diffraction) and relative intensities of observable diffraction peaks. Patterns may be experimentally determined, or computed based on crystal structure and Bragg's law. It is most often used to identify substances based on x-ray diffraction data, and is designed for use with a diffractometer. The PDF contains more than a million unique material data sets. Each data set contains diffraction, crystallographic and bibliographic data, as well as experimental, instrument and sampling conditions, and select physical properties in a common standardized format. The organization was founded in 1941 as the Joint Committee on Powder Diffraction Standards (JCPDS). In 1978, the name of the organization was changed to the current name to highlight the global commitment of this scientific endeavor. The IC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gandolfi Camera
A field camera is a view camera that can be folded in a compact size. Modern designs are little different from the first folding field cameras from the 19th century. In general they have more limited camera movements than monorail cameras, but when folded are relatively compact and portable. Modern field cameras originate from the early interlocking box cameras of the 19th century. Rather than the wooden box used in 19th-century cameras, modern models substitute bellows to reduce the bulk of the cameras and make them easier to use outside the studio. Although they have less flexibility than monorail cameras, modern field cameras tend to have most camera movements for the front standard, i.e. lens rise/fall/shift/tilt/swing, but are usually more limited in back movements, sometimes having only tilt/swing. They usually use sheet film, in sizes from 6x9cm (2.4×3.6") to 20×24 inches (e.g., the Polaroid 20×24 camera), but the most popular "standard" sizes are 4×5 and 8×1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Powder Diffraction
Powder diffraction is a scientific technique using X-ray, neutron, or electron diffraction on powder or microcrystalline samples for structural characterization of materials. An instrument dedicated to performing such powder measurements is called a powder diffractometer. Powder diffraction stands in contrast to single crystal diffraction techniques, which work best with a single, well-ordered crystal. Explanation A diffractometer produces electromagnetic radiation (waves) with known wavelength and frequency, which is determined by their source. The source is often x-rays, because they are the only kind of energy with the optimal wavelength for inter-atomic-scale diffraction. However, electrons and neutrons are also common sources, with their frequency determined by their de Broglie wavelength. When these waves reach the sample, the incoming beam is either reflected off the surface, or can enter the lattice and be diffracted by the atoms present in the sample. If the atoms ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ignacy Domeyko
Ignacy Domeyko or Domejko, pseudonym: ''Żegota'' ( es, Ignacio Domeyko, ; 31 July 1802 – 23 January 1889) was a Polish geologist, mineralogist, educator, and founder of the University of Santiago, in Chile. Domeyko spent most of his life, and died, in his adopted country, Chile. After a youth passed in partitioned Poland, Domeyko participated in the Polish–Russian War 1830–31. Upon Russian victory, he was exiled, spending part of his life in France (where he had gone with a fellow Philomath, Polish poet Adam Mickiewicz) before eventually settling in Chile, whose citizen he became. He lived some 50 years in Chile and made major contributions to the study of that country's geography, geology and mineralogy. His observations on the circumstances of poverty-stricken miners and of their wealthy exploiters had a profound influence on those who would go on to shape Chile's labor movement. Domeyko is seen as having had close ties to several countries and thus in 2002, when U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Diffraction
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their crystallographic disorder, and various other information. Since many materials can form crystals—such as salts, metals, minerals, semiconductors, as well as various inorganic, organic, and biological molecules—X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences among vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Difference Density Map
In X-ray crystallography, a difference density map shows the spatial distribution of the difference between the measured electron density of the crystal and the electron density explained by the current model. These coefficients are derived from the gradient of the likelihood function of the observed structure factors on the basis of the current model. Display Conventionally, they are displayed as isosurfaces with positive density—electron density where there's nothing in the model, usually corresponding to some constituent of the crystal that hasn't been modelled, for example a ligand In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's ele ... or a crystallisation adjutant -- in green, and negative density—parts of the model not backed up by electron density, indicating either that an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patterson Function
The Patterson function is used to solve the phase problem in X-ray crystallography. It was introduced in 1935 by Arthur Lindo Patterson while he was a visiting researcher in the laboratory of Bertram Eugene Warren at MIT. The Patterson function is defined as :P(u,v,w) = \sum\limits_ \left, F_\^2 \;e^. It is essentially the Fourier transform of the intensities rather than the structure factors. The Patterson function is also equivalent to the electron density In quantum chemistry, electron density or electronic density is the measure of the probability of an electron being present at an infinitesimal element of space surrounding any given point. It is a scalar quantity depending upon three spatial ... convolved with its inverse: :P\left(\vec\right) = \rho\left(\vec\right) * \rho\left(-\vec\right). Furthermore, a Patterson map of ''N'' points will have peaks, excluding the central (origin) peak and any overlap. The peaks' positions in the Patterson function are the int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
