|
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 thos ... [...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 thos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), 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, 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 (material), lime, ''calx'' (genitive calcis) with the suffix "-ite" used to name minerals. It is thus etymologically related to chalk. When applied by archaeology, archaeologists and stone trade pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 arago ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ikaite
Ikaite is the mineral name for the hexahydrate of calcium carbonate, CaCO3·6H2O. Ikaite tends to form very steep or spiky pyramidal crystals, often radially arranged, of varied sizes from thumbnail size aggregates to gigantic salient spurs. It is only found in a metastable state and decomposes rapidly by losing most of its water content once removed from near-freezing water. This "melting mineral" is more commonly known through its pseudomorphs. Distribution It is usually considered a rare mineral, but this is likely due to difficulty in preserving samples. It was first discovered in nature by the Danish mineralogist Pauly in the Ikka (then spelt Ika) fjord in southwest Greenland, close to Ivittuut, the locality of the famous cryolite deposit. Here ikaite occurs in truly spectacular towers or columns (up to tall) growing out of the fjord floor towards the surface water, where they are naturally truncated by waves, or unnaturally by the occasional boat. At the Ikka Fjord, it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monohydrocalcite
Monohydrocalcite is a mineral that is a hydrous form of calcium carbonate, CaCO3·H2O. It was formerly also known by the name hydrocalcite, which is now discredited by the IMA. It is a trigonal mineral which is white when pure. Monohydrocalcite is not a common rock-forming mineral, but is frequently associated with other calcium and magnesium carbonate minerals, such as calcite, aragonite, lansfordite, and nesquehonite. Monohydrocalcite has been observed in air conditioning systems, and in moonmilk deposits in caves, both probably formed from spray of carbonate rich fluids. It is well known in Robe on the Limestone Coast of South Australia as a component of beach sands of Lake Fellmongery and Lake Butler, where it is believed to be formed from algal spume. Other lacustrine deposits include Lake Issyk-Kul, Kyrgyzstan, Lake Kivu, Democratic Republic of the Congo, and Solar Lake, Sinai. It has been reported as a significant component of the decomposition of ikaite in the towers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostwald Ripening
Ostwald ripening is a phenomenon observed in solid solutions or liquid sols that describes the change of an inhomogeneous structure over time, i.e., small crystals or sol particles dissolve, and redeposit onto larger crystals or sol particles. Dissolution of small crystals or sol particles and the redeposition of the dissolved species on the surfaces of larger crystals or sol particles was first described by Wilhelm Ostwald in 1896. For colloidal systems, Ostwald ripening is also found in water-in-oil emulsions, while flocculation is found in oil-in-water emulsions. Mechanism This thermodynamically-driven spontaneous process occurs because larger particles are more energetically favored than smaller particles. This stems from the fact that molecules on the surface of a particle are energetically less stable than the ones in the interior. Consider a cubic crystal of atoms: all the atoms inside are bonded to 6 neighbours and are quite stable, but atoms on the surface are onl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Minerals Named After People
This is a list of minerals named after people. The chemical composition follows name. A *Abelsonite: C31H32N4Ni – American physicist Philip Hauge Abelson (1913–2004)alfred *Abswurmbachite: Cu2+Mn3+6O8SiO4 – German mineralogist Irmgard Abs-Wurmbach * Adamite: Zn2AsO4OH – French mineralogist Gilbert Joseph Adam (1795–1881) *Agrellite: NaCa2Si4O10F – English optical mineralogist Stuart Olof Agrell (1913–1996) * Agricolaite: K4(UO2)(CO3)3 – German scholar Georgius Agricola (1494–1555) * Aheylite: Fe2+Al6 (PO4)2sub>2·4H2O – American geologist Allen V. Heyl (1918–2008) * Albrechtschraufite: Ca4Mg(UO2)2(CO3)6F2·17H2O – Albrecht Schrauf (1837–1897), professor of mineralogy, University of Vienna * Alexandrite (variety of chrysoberyl): – Tsar Alexander II of Russia (1818–1881) *Alforsite: Ba5Cl(PO4)3 – American geologist John T. Alfors (1930–2005) *Allabogdanite: (Fe,Ni)2P – Alla Bogdanova, Geological Ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Minerals
This is a list of minerals for which there are articles on Wikipedia. Minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various ''species''. Within a mineral species there may be variation in physical properties or minor amounts of impurities that are recognized by mineralogists or wider society as a mineral ''variety''. Mineral variety names are listed after the valid minerals for each letter. For a more complete listing of all mineral names, see List of minerals recognized by the International Mineralogical Association. A :Varieties that are not valid species: *Adamantine spar (variety of corundum) *Agate (variety of chalcedony and quartz) *Alabaster (variety of gypsum) *Alexandrite (variety of chrysoberyl) *Allingite (synonym of amber) *Alum *Amazonite (variety of microcline) *Amethyst (purple variety of quartz) *Ametrine (variety of quartz) *Ammolite (organic; also a gems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JCPDS
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 ICDD ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge University Botanic Garden
The Cambridge University Botanic Garden is a botanical garden located in Cambridge, England, associated with the university Department of Plant Sciences (formerly Botany School). It lies between Trumpington Road to the west, Bateman Street to the north and Hills Road to the east. The garden covers an area of 16 hectares (40 acres). The site is almost entirely on level ground and in addition to its scientific value, the garden is highly rated by gardening enthusiasts. It holds a plant collection of over 8,000 plant species from all over the world to facilitate teaching and research. The garden was created for the University of Cambridge in 1831 by Professor John Stevens Henslow (Charles Darwin's mentor) and was opened to the public in 1846. The third-highest temperature recorded in the UK, 38.7 °C (101.7 °F), was recorded on 25 July 2019 at the garden. History Walkerian Garden After several unsuccessful attempts during the 16th, 17th, and early 18th centuries ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saxifraga
''Saxifraga'' is the largest genus in the family Saxifragaceae, containing about 465 species of holarctic perennial plants, known as saxifrages or rockfoils. The Latin word ''saxifraga'' means literally "stone-breaker", from Latin ' ("rock" or "stone") + ' ("to break"). It is usually thought to indicate a medicinal use for treatment of urinary calculi (known as kidney or bladder stones), rather than breaking rocks apart. Description Most saxifrages are small perennial, biennial (e.g. '' S. adscendens'') or annual (e.g. '' S. tridactylites'') herbaceous plants whose basal or cauline leaves grow close to the ground, often in a rosette. The leaves typically have a more or less incised margin; they may be succulent, needle-like and/or hairy, reducing evaporation. The inflorescence or single flower clusters rise above the main plant body on naked stalks. The small actinomorphic hermaphrodite flowers have five petals and sepals and are usually white, but red to yellow in some specie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
