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Katayamalite
Katayamalite is a cyclosilicate mineral that was named in honor of mineralogist and professor Nobuo Katayama. It was approved in 1982 by the International Mineralogical Association, and was first published a year later. Relation with baratovite Katayamalite is the hydroxyl analogue of baratovite and the hydroxyl end member of the series, but was first described as a fluor-dominant mineral. Some scientists claim it to be rather hydroxyl- than fluor dominant, which would make baratovite isostructural with it. It would make the two minerals the same species, with baratovite having priority. As the case hadn't been clarified, katayamalite remains an IMA-approved mineral until this day. Chemical properties Katayamalite mainly consists of oxygen (43.16%), silicon (24.25%), calcium (20.18%), but otherwise contains titanium (6.89%), potassium (2.81%), lithium (1.50%). It has trace amounts of fluorine (0.68%), sodium (0.41%) and hydrogen (0.11%) in its composition as well. It has a bar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baratovite
Baratovite is a very rare cyclosilicate mineral named after Rauf Baratovich Baratov from Tajikistan. It was discovered in 1974 at Dara-Pioz glacier, Tajikistan, and was approved by the International Mineralogical Association only a year later in 1975. The glacier gives home to 133 valid species, and is the type locality of 33 minerals, one of which is baratovite. Properties It's a titanium rich variant of aleksandrovite. Although it is considered to be rich in titanium, and the fact it is the fluor-dominant analog of katayamalite, some mineralogist consider baratovite to be a hydroxyl-, rather than fluorine-dominant. In this case, it would make katayamalite the same species, as baratovite is isostructural with it. Common impurities include magnesium, natrium, iron and niobium. Baratovite was originally described to have a 3 - 3.5 hardness on the Mohs scale, which was later corrected to 5 - 6. It has a perfect cleavage in two directions crossing basal plane, in , and the luste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoclinic
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a parallelogram prism (geometry), 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 class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered ''radioactive''. Three of the most common types of decay are Alpha decay, alpha, Beta decay, beta, and Gamma ray, gamma decay. The weak force is the Fundamental interactions, mechanism that is responsible for beta decay, while the other two are governed by the electromagnetic force, electromagnetic and nuclear forces. Radioactive decay is a randomness, random process at the level of single atoms. According to quantum mechanics, quantum theory, it is impossible to predict when a particular atom will decay, regardless of how long the atom has existed. However, for a significant number of identical atoms, the overall decay rate can be expressed as a decay constant or as a half-life. The half-lives of radioactive atoms have a huge range: f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclosilicate
Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, the crystalline forms of silica (silicon dioxide, ) are usually considered to be Silicate mineral#Tectosilicates, tectosilicates, and they are classified as such in the Dana system (75.1). However, the Nickel-Strunz system classifies them as oxide minerals (4.DA). Silica is found in nature as the mineral quartz, and its polymorphism (materials science), polymorphs. On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as a result of the processes that have been forming and re-working the crust for billions of years. These processes include partial melting, crystallization, fractionation, metamorphism, weathering, and diagenesis. Living organisms also contribute to this carbonate–silicate cycle, geologic cycle. For example, a type of plankton ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Minerals'; p. 1. In the series ''Geology: Landforms, Minerals, and Rocks''. Rosen Publishing Group. The Geology, geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or organic compounds in the sense of chemistry (such as mellite). Moreover, living organisms often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks. The concept of mineral is distinct from rock (geology), rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral or may be an aggregate (geology), aggregate of two or more different types of minerals, spaci ... [...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] |
Isostructural
Isostructural chemical compounds have similar chemical structures. " Isomorphous" when used in the relation to crystal structures is not synonymous: in addition to the same atomic connectivity that characterises isostructural compounds, isomorphous substances crystallise in the same space group and have the same unit cell dimensions. The IUCR definition used by crystallographers is: Examples include: *I- Gold(I) bromide is isostructural with gold(I) chloride *Borazine is isostructural with benzene * Indium(I) bromide is isostructural with β- thallium(I) iodide and has a distorted rock salt structure. Many minerals are isostructural when they differ only in the nature of a cation. Compounds which are isoelectronic usually have similar chemical structures. For example, methane, CH4, and the ammonium ion, NH4+, are isoelectric and are isostructural as both have a tetrahedral structure. The C-H and N-H bond lengths are different and crystal structures are completely different bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Ray American Petroleum Institute Units
Gamma (; uppercase , lowercase ; ) is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop . In Modern Greek, this letter normally represents a voiced velar fricative , except before either of the two front vowels (/e/, /i/), where it represents a voiced palatal fricative ; while /g/ in foreign words is instead commonly transcribed as γκ). In the International Phonetic Alphabet and other modern Latin-alphabet based phonetic notations, it represents the voiced velar fricative. History The Greek letter Gamma Γ is a grapheme derived from the Phoenician letter (''gīml'') which was rotated from the right-to-left script of Canaanite to accommodate the Greek language's writing system of left-to-right. The Canaanite grapheme represented the /g/ phoneme in the Canaanite language, and as such is cognate with ''gimel'' ג of the Hebrew alphabet. Based on its name, the lett ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triclinic
class=skin-invert-image, 180px, Triclinic (a ≠ b ≠ c ≠ a and α, β, γ, 90° pairwise different) In crystallography, the triclinic (or anorthic) crystal system is one of the seven crystal systems. A crystal system is described by three basis vectors. In the triclinic system, the crystal is described by vectors of unequal length, as in the orthorhombic system. In addition, the angles between these vectors must all be different and may not include 90°. The triclinic lattice is the least symmetric of the 14 three-dimensional Bravais lattices. It has (itself) the minimum symmetry all lattices have: points of inversion at each lattice point and at 7 more points for each lattice point: at the midpoints of the edges and the faces, and at the center points. It is the only lattice type that itself has no mirror planes. Crystal classes The triclinic crystal system class names, examples, Schönflies notation, Hermann-Mauguin notation, point groups, International Tables for C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sugilite
Sugilite ( ) is a relatively rare pink to purple cyclosilicate mineral with the complex chemical formula K Na2( Fe, Mn, Al)2 Li3 Si12 O30. Sugilite crystallizes in the hexagonal system with prismatic crystals. The crystals are rarely found and the form is usually massive. It has a Mohs hardness of 5.5–6.5 and a specific gravity of 2.75–2.80. It is mostly translucent. Sugilite was first described in 1944 by the Japanese petrologist Ken-ichi Sugi (1901–1948) for an occurrence on Iwagi Islet, Japan, where it is found in an aegirine syenite intrusive stock. It is found in a similar environment at Mont Saint-Hilaire, Quebec, Canada. In the Wessels mine in Northern Cape Province of South Africa, sugilite is mined from a strata-bound manganese deposit. It is also reported from Liguria and Tuscany, Italy; New South Wales, Australia and Madhya Pradesh, India. Sugilite is commonly pronounced with a soft "g", as in "ginger". However, as with most minerals, its pronunciat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albite
Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. It represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula . It is a tectosilicate. Its color is usually pure white, hence its name from Latin, . It is a common constituent in felsic rocks. Properties Albite crystallizes with triclinic pinacoidal forms. Its specific gravity is about 2.62 and it has a Mohs hardness of 6 to 6.5. Albite almost always exhibits crystal twinning often as minute parallel striations on the crystal face. Albite often occurs as fine parallel segregations alternating with pink microcline in perthite as a result of exolution on cooling. There are two variants of albite, which are referred to as 'low albite' and 'high albite'; the latter is also known as 'analbite'. Although both variants are triclinic, they differ in the volume of their unit cell, which is slightly larger for the 'high' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
