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Aragonite
Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including precipitation from marine and freshwater environments. The crystal lattice of aragonite differs from that of calcite, resulting in a different crystal shape, an orthorhombic crystal system with acicular crystal. Repeated twinning results in pseudo-hexagonal forms. Aragonite may be columnar or fibrous, occasionally in branching helictitic forms called ''flos-ferri'' ("flowers of iron") from their association with the ores at the Carinthian iron mines. Occurrence The type location for aragonite is Molina de Aragón in the Province of Guadalajara in Castilla-La Mancha, Spain, for which it was named in 1797. Aragonite is found in this locality as cyclic twins inside gypsum and marls of the Keuper facies of the Triassic. This type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oolitic Aragonite Sand
Oolitic aragonite sand is composed of the calcium carbonate mineral, aragonite, with an egg-like shape (" oolitic" from the Ancient Greek word ᾠόν for "egg") and sand grain size. This sand type forms in tropical waters through precipitation, sedimentation, and microbial activity, and is indicative of high energy environments. The production of oolitic aragonite sand in the Bahamas surpasses anyplace else in the world. Changes in seawater chemistry and paleoenvironments can be interpreted by the sand's chemical composition and structure. Formation Oolitic aragonite sand forms in high-salinity waters that are turbulent, shallow, and warm. The sand starts to form around a nucleus of calcium carbonate, such as a peloid, shell fragment, or foraminifer. The nucleus is coated with a thin layer of crystalline carbonate to form the cortex of the ooid. Compared to other types of sand formation that involve the weathering and erosion of a larger rock by turbulent waters, oolitic ara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaterite
Vaterite is a mineral, a polymorph of calcium carbonate ( Ca C O3). It was named after the German mineralogist Heinrich Vater. It is also known as mu- calcium carbonate (μ-CaCO3). Vaterite belongs to the hexagonal crystal system, whereas calcite is trigonal and aragonite is orthorhombic. Vaterite, like aragonite, is a metastable phase of calcium carbonate at ambient conditions at the surface of the earth. As it is less stable than either calcite or aragonite, vaterite has a higher solubility than either of these phases. Therefore, once vaterite is exposed to water, it converts to calcite (at low temperature) or aragonite (at high temperature: ~60 °C). At 37 °C for example a solution-mediated transition from vaterite to calcite occurs, where the vaterite dissolves and subsequently precipitates as calcite assisted by an Ostwald ripening process. However, vaterite does occur naturally in mineral springs, organic tissue, gallstones, urinary calculi and plants. In tho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound 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 geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or are 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, 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 of two or more different types of minerals, spacially segregated into disti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses. Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite over timescales of days or less at temperatures exceeding 300 °C, and vaterite is even less stable. Etymology Calcite is derived from the German ''Calcit'', a term from the 19th century that came from the Latin word for lime, ''calx'' (genitive calcis) with the suffix "-ite" used to name minerals. It is thus etymologically related to chalk. When applied by archaeologists and stone trade professionals, the term alabaster is used not just as in geology and mineralogy, where it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ochtinská Aragonite Cave
Ochtinská Aragonite Cave ( sk, Ochtinská aragonitová jaskyňa, hu, Martonházi-aragonitbarlangthe Magyar Wikipedia article uses a different title) is a unique aragonite cave situated in southern Slovakia, near Rožňava. Although only 300 m long, it is famous for its rare aragonite formations. Description There are only three aragonite caves discovered in the world so far. In the so-called Milky Way Hall, the main attraction of the cave, white branches and clusters of aragonite shine like stars in the Milky Way. The cave was discovered by Martin Cangár and Jiri Prosek in 1954 and opened to the public in 1972. Along with other caves of the Slovak Karst, it is included in the UNESCO World Heritage list as a component of Caves of Aggtelek Karst and Slovak Karst site. See also *List of caves in Slovakia There are more than 2,400 caves in Slovakia, of which more than 400 have been explored so far. New caves are being discovered constantly. Caves open to the public * caves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aragonite, Utah
The Aragonite Hazardous Waste Incinerator is a waste disposal facility currently operated by Clean Harbors. It is located in Aragonite, Tooele County, Utah, United States, located in the western portion of the state. Site geography and early history The Utah Test and Training Range lies to the west and the Dugway Proving Grounds lie to the southwest. Interstate 80, exit 56 provides access to Aragonite. The site lies northwest of the Cedar Mountains. The low Grassy Mountains lie to the north. Aragonite lies along the Hastings Cutoff, a historical transmontane route taken by nineteenth-century pioneers. Aragonite was established in the early twentieth century for the mining of aragonite, though all mining operations in the area have ceased. A 1950s-era mining guide described a small townsite, but the area is now uninhabited and almost totally demolished. The historical Aragonite site has been described as "an old mining town from the early 20th century that mined aragonite. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthodite
Anthodites (Greek ἄνθος ''ánthos'', "flower", ''-ode'', adjectival combining form, ''-ite'' adjectival suffix) are speleothems (cave formations) composed of long needle-like crystals situated in clusters which radiate outward from a common base. The "needles" may be quill-like or feathery. Most anthodites are made of the mineral aragonite (a variety of calcium carbonate, CaCO3), although some are composed of gypsum (CaSO4·2H2O). The term ''anthodite'' is first cited in the scientific literature in 1965 by Japanese researcher N. Kashima, who described "flower-like dripstone" composed of "an alternation of calcite and aragonite". Structure, composition and appearance The individual crystals of anthodites develop in a form described as "acicular" (needle-like) and often branch out as they grow. They usually grow downward from a cave's ceiling. Aragonite crystals are contrasted with those made of calcite (another variety of calcium carbonate) in that the latter tend to be s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Twinning
Crystal twinning occurs when two or more adjacent crystals of the same mineral are oriented so that they share some of the same crystal lattice points in a symmetrical manner. The result is an intergrowth of two separate crystals that are tightly bonded to each other. The surface along which the lattice points are shared in twinned crystals is called a composition surface or twin plane. Crystallographers classify twinned crystals by a number of twin laws. These twin laws are specific to the crystal structure. The type of twinning can be a diagnostic tool in mineral identification. Deformation twinning, in which twinning develops in a crystal in response to a shear stress, is an important mechanism for permanent shape changes in a crystal.Courtney, Thomas H. (2000) ''Mechanical Behavior of Materials'', 2nd ed. McGraw Hill. Definition Twinning is a form of symmetrical intergrowth between two or more adjacent crystals of the same mineral. It differs from the ordinary random ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slovakia
Slovakia (; sk, Slovensko ), officially the Slovak Republic ( sk, Slovenská republika, links=no ), is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the southwest, and the Czech Republic to the northwest. Slovakia's mostly mountainous territory spans about , with a population of over 5.4 million. The capital and largest city is Bratislava, while the second largest city is Košice. The Slavs arrived in the territory of present-day Slovakia in the fifth and sixth centuries. In the seventh century, they played a significant role in the creation of Samo's Empire. In the ninth century, they established the Principality of Nitra, which was later conquered by the Principality of Moravia to establish Great Moravia. In the 10th century, after the dissolution of Great Moravia, the territory was integrated into the Principality of Hungary, which then became the Kingdom of Hungary in 1000. In 124 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molina De Aragón
Molina de Aragón is a municipality located in the province of Guadalajara, Castile-La Mancha, Spain. According to the 2009 census ( INE), the municipality had a population of 3,671 inhabitants. It holds the record (−28.2 °C) for the lowest temperature measured by a meteorological station in Spain. It was the seat of the taifa of Molina, a Moorish independent state, before it was reconquered by the Christians of Alfonso I of Aragon in 1129. On 21 April 1154 Manrique Pérez de Lara issued a sweeping ''fuero'' to the town of Molina, which he was building into a semi-independent fief.Simon Barton, ''The Aristocracy in Twelfth-century León and Castile'' (Cambridge: Cambridge University Press, 1997), 265. He and his descendants claimed to rule Molina ''Dei gratia'' (" by the grace of God"). Molina is also the type location of the carbonate mineral aragonite. Main sights *Medieval alcazar (10th–11th centuries), the largest in the province *Roman bridge (''Puente Viejo'') ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthorhombic Crystal System
In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a rectangular base (''a'' by ''b'') and height (''c''), such that ''a'', ''b'', and ''c'' are distinct. All three bases intersect at 90° angles, so the three lattice vectors remain mutually orthogonal. Bravais lattices There are four orthorhombic Bravais lattices: primitive orthorhombic, base-centered orthorhombic, body-centered orthorhombic, and face-centered orthorhombic. For the base-centered orthorhombic lattice, the primitive cell has the shape of a right rhombic prism;See , row oC, column Primitive, where the cell parameters are given as a1 = a2, α = β = 90° it can be constructed because the two-dimensional centered rectangular base layer can also be described with primitive rhombic axes. Note that the length a of the primit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helictite
A helictite is a speleothem (cave-formed mineral) found in a limestone cave that changes its axis from the vertical at one or more stages during its growth. Helictites have a curving or angular form that looks as if they were grown in zero gravity. They are most likely the result of capillary forces acting on tiny water droplets, a force often strong enough at this scale to defy gravity. Helictites are, perhaps, the most delicate of cave formations. They are usually made of needle-form calcite and aragonite. Helictite forms have been described in several types: ribbon helictites, saws, rods, butterflies, "hands", curly-fries, and "clumps of worms". They typically have radial symmetry. They can be easily crushed or broken by the slightest touch. Because of this, helictites are rarely seen within arm's reach in tourist Tourism is travel for pleasure or business; also the theory and practice of touring, the business of attracting, accommodating, and entertaining tourists, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
