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Potassic-magnesio-fluoro-arfvedsonite
Potassic-magnesio-fluoro-arfvedsonite is an amphibole mineral first discovered in Quebec, Canada, in an area which is part of the Canadian Shield which is where some of the oldest exposed rocks are that can date back to over 4 billion years ago. Potassic-magnesio-fluoro-arfvedsonite is also the mineral with the longest name of any mineral with 34 letters and 37 characters. Occurrence Potassic-magnesio-fluoro-arfvedsonite is found in Igneous rock, igneous rocks. The rocks it is found in are classified as a complex mafic ultrapotassic Peralkaline rock, peralkaline igneous rock with high Silicon dioxide, silica contents. Most commonly it is found with Lamproite. Potassic-magnesio-fluoro-arfvedsonite is a uniquely rare mineral, as it occurs in small amounts in very few locations around the world. Physical properties Potassic-magnesio-fluoro-arfvedsonite is a bluish-gray mineral with a vitreous luster. It exhibits a hardness of 6 on the Mohs scale of mineral hardness, Mohs hardness ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicate
A silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is also used for any salt of such anions, such as sodium metasilicate; or any ester containing the corresponding chemical group, such as tetramethyl orthosilicate. The name "silicate" is sometimes extended to any anions containing silicon, even if they do not fit the general formula or contain other atoms besides oxygen; such as hexafluorosilicate . Most commonly, silicates are encountered as silicate minerals. For diverse manufacturing, technological, and artistic needs, silicates are versatile materials, both natural (such as granite, gravel, and garnet) and artificial (such as Portland cement, ceramics, glass, and waterglass). Structural principles In most silicates, a silicon atom occupies the center of an idealized tetrahedron whose cor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troms Og Finnmark
Troms og Finnmark (; ; ; ) was a county in northern Norway that existed from 2020 to 2023. The county was established on 1 January 2020 as the result of a regional reform. It was the largest county by area in Norway, encompassing about , and was formed by the merger of the former Finnmark and Troms counties in addition to Tjeldsund Municipality from Nordland county. The administrative centre of the county was split between two towns. The political and administrative offices were based in the city of Tromsø (the seat of the old Troms county). The county governor was based in the town of Vadsø (the seat of the old Finnmark county). The two towns are about apart, approximately a 10-hour drive by car. On 15 June 2022, the parliament decided to split the county back into Finnmark and Troms beginning on 1 January 2024, with Tjeldsund Municipality assigned to Troms county (Tjeldsund had been part of Nordland county before 2020). Geography Troms og Finnmark was the northernm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Group
In mathematics, physics and chemistry, a space group is the symmetry group of a repeating pattern in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of the pattern that leave it unchanged. In three dimensions, space groups are classified into 219 distinct types, or 230 types if chiral copies are considered distinct. Space groups are discrete cocompact groups of isometries of an oriented Euclidean space in any number of dimensions. In dimensions other than 3, they are sometimes called Bieberbach groups. In crystallography, space groups are also called the crystallographic or Fedorov groups, and represent a description of the symmetry of the crystal. A definitive source regarding 3-dimensional space groups is the ''International Tables for Crystallography'' . History Space groups in 2 dimensions are the 17 wallpaper groups which have been known for several centuries, though the proof that the list ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoclinic Crystal System
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a parallelogram prism. Hence two pairs of vectors are perpendicular (meet at right angles), while the third pair makes an angle other than 90°. Bravais lattices Two monoclinic Bravais lattices exist: the primitive monoclinic and the base-centered monoclinic. For the base-centered monoclinic lattice, the primitive cell has the shape of an oblique rhombic prism;See , row mC, column Primitive, where the cell parameters are given as a1 = a2, α = β it can be constructed because the two-dimensional centered rectangular base layer can also be described with primitive rhombic axes. The length a of the primitive cell below equals \frac \sqrt of the conventional cell above. Crystal classes The table below organizes the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Crystallography
X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to Diffraction, diffract in specific directions. By measuring the angles and intensities of the X-ray diffraction, a crystallography, crystallographer can produce a three-dimensional picture of the density of electrons within the crystal and the positions of the atoms, as well as their chemical bonds, crystallographic disorder, and other information. 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 between various materials, especially minerals and alloys. The method has also revealed the structure and function of many biological molecules, including vitamins, drugs, proteins and nucleic acids such as DNA. X-ray crystall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Mineralogical Association
Founded in 1958, the International Mineralogical Association (IMA) is an international group of 40 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 5000 plus known mineral species. The IMA is affiliated with the International Union of Geological Sciences (IUGS). The Association supports the activities of Commissions and Working Groups involved on certain aspects of mineralogical practice and facilitates interactions among mineralogists by sponsoring and organising meetings. In particular, the IMA holds its general meeting every four years. The last meeting was scheduled in 2022 in Lyon, France. Presidents The presidents of the IMA have been: * since 2024: Eiji Ohtani ** Tohoku University * 2022–2024: Hans-Peter Schertl ** Bochum University * 2020–2022: Anhuai Lu ** Peking University *2018–2020: Patrick Cordier ** Université de Lille *2016–2018: Peter C. Burns ** University of Notre Dame *2014–2016 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proterozoic
The Proterozoic ( ) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, and is the longest eon of Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozoic, and is the most recent part of the Precambrian "supereon". The Proterozoic is subdivided into three geologic eras (from oldest to youngest): the Paleoproterozoic, Mesoproterozoic and Neoproterozoic. It covers the time from the appearance of free oxygen in Earth's atmosphere to just before the proliferation of complex life on the Earth during the Cambrian Explosion. The name ''Proterozoic'' combines two words of Greek origin: meaning "former, earlier", and , meaning "of life". Well-identified events of this eon were the transition to an oxygenated atmosphere during the Paleoproterozoic; the evolution of eukaryotes via symbiogenesis; several global glaciations, which produced the 300 million years-long Huronian glaciation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archean
The Archean ( , also spelled Archaean or Archæan), in older sources sometimes called the Archaeozoic, is the second of the four geologic eons of Earth's history of Earth, history, preceded by the Hadean Eon and followed by the Proterozoic and the Phanerozoic. The Archean represents the time period from (million years ago). The Late Heavy Bombardment is hypothesized to overlap with the beginning of the Archean. The Huronian glaciation occurred at the end of the eon. The Earth during the Archean was mostly a ocean world, water world: there was continental crust, but much of it was under an ocean deeper than today's oceans. Except for some rare Relict (geology), relict crystals, today's oldest continental crust dates back to the Archean. Much of the geological detail of the Archean has been destroyed by subsequent activity. The Earth's atmosphere was also vastly different in atmospheric chemistry, composition from today's: the prebiotic atmosphere was a reducing atmosphere rich in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Las Vegas Valley
The Las Vegas Valley is a major metropolitan area in the Southern Nevada, southern part of the U.S. state of Nevada, and the second largest in the Southwestern United States. The state's largest urban agglomeration, the Las Vegas Metropolitan Statistical Area is coextensive since 2003 with Clark County, Nevada. The Valley is largely defined by the Las Vegas Valley land formation, a Depression (geology), basin area surrounded by mountains to the north, south, east and west of the metropolitan area. The Valley is home to the three largest incorporated cities in Nevada: Las Vegas, Henderson, Nevada, Henderson and North Las Vegas, Nevada, North Las Vegas. Eleven unincorporated towns governed by the Clark County government are part of the Las Vegas Township and constitute the largest community in the state of Nevada. The names Las Vegas and Vegas are interchangeably used to indicate the Valley, Las Vegas Strip, the Strip, and the city, and as a brand by the Las Vegas Convention and V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dakhla-Oued Ed-Dahab
Dakhla-Oued Ed-Dahab () is one of the twelve regions of Morocco. Before September 2015 it was known as Oued Ed-Dahab-Lagouira (). It is situated in the disputed territory of Western Sahara, considered by Morocco to be the southern part of the country. The Polisario Front and other independence-seeking Sahrawis consider this to be a part of the Sahrawi Arab Democratic Republic. The United Nations and most countries do not recognize Moroccan sovereignty over the area. The region covers an area of 50,880 km2 and had a population of 142,955 according to the 2014 census. The capital is the coastal city of Dakhla, formerly known as Villa Cisneros. The region comprises two provinces: History On 15 December 2023, the Polisario Front The Popular Front for the Liberation of Saguia el-Hamra and Río de Oro (Spanish language, Spanish: ; ), better known by its acronym Polisario Front, is a Sahrawi nationalism, Sahrawi nationalist liberation movement seeking to end the occupati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Montepuez District
Montepuez District is a district of Cabo Delgado Province in northern Mozambique. It seat lies at Montepuez Montepuez is the second largest city in the province of Cabo Delgado in Mozambique Mozambique, officially the Republic of Mozambique, is a country located in Southeast Africa bordered by the Indian Ocean to the east, Tanzania to the nort ... town. External linksGovernment profile {{coord, 13, 07, S, 39, 00, E, display=title Districts in Cabo Delgado Province ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphibole
Amphibole ( ) is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is Amp. Amphiboles can be green, black, colorless, white, yellow, blue, or brown. The International Mineralogical Association currently classifies amphiboles as a mineral supergroup, within which are two groups and several subgroups. Mineralogy Amphiboles crystallize into two crystal systems, monoclinic and orthorhombic. In chemical composition and general characteristics they are similar to the pyroxenes. The chief differences from pyroxenes are that (i) amphiboles contain essential hydroxyl (OH) or halogen (F, Cl) and (ii) the basic structure is a double chain of tetrahedra (as opposed to the single chain structure of pyroxene). Most apparent, in hand specimens, is that amphiboles form oblique cleavage planes (at around 120 degrees), wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
