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Vladimirite
Vladimirite is a rare calcium arsenate mineral with a formula of Ca5(HAsO4)2(AsO4)2·5H2O. It is named after the Vladimirovskoye deposit in Russia, where it was discovered in the 1950s. Vladimirite is monoclinic-prismatic, which means crystallographically, it contains three axes of unequal length and the angles between two of the axes are 90 degrees, and one is less than 90 degrees. It belongs to the space group P21/c. The mineral also has an orthorhombic polytype. In terms of its optical properties, vladimirite is anisotropic which means the velocity of light varies depending on direction through the mineral. Relief is a diagnostic characteristic of a mineral in plane polarized light that refers to the various ways different minerals "stand out". Vladimirite's calculated relief is 1.65-1.661, which is moderate. It is colorless in plane polarized light, and it is weakly pleochroic. Pleochroism is the variety of colors under plane polarized light displayed by crystals at vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arsenate Minerals
Arsenate minerals usually refer to the naturally occurring orthoarsenates, possessing the (AsO4)3− anion group and, more rarely, other arsenates with anions like AsO3(OH)2− (also written HAsO42−) (example: pharmacolite Ca(AsO3OH).2H2O) or (very rarely) sO2(OH)2sup>− (example: andyrobertsite). Arsenite minerals are much less common. Both the Dana and the Strunz mineral classifications place the arsenates in with the phosphate minerals. Example arsenate minerals include: * Annabergite Ni3(AsO4)2·8H2O *Austinite CaZn(AsO4)(OH) *Clinoclase Cu3(AsO4)(OH)3 *Conichalcite CaCu(AsO4)(OH) * Cornubite Cu5(AsO4)2(OH)4 *Cornwallite Cu2+5(AsO4)2(OH)2 *Erythrite Co3(AsO4)2·8H2O *Mimetite Pb5(AsO4)3Cl * Olivenite Cu2(AsO4)OH Nickel–Strunz Classification -08- Phosphates IMA-CNMNC proposes a new hierarchical scheme (Mills et al., 2009). This list uses it to modify the Classification of Nickel–Strunz ( mindat.org, 10 ed, pending publication). *Abbreviations: **"*" - discredi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arsenate Mineral
Arsenate minerals usually refer to the naturally occurring orthoarsenates, possessing the (AsO4)3− anion group and, more rarely, other arsenates with anions like AsO3(OH)2− (also written HAsO42−) (example: pharmacolite Ca(AsO3OH).2H2O) or (very rarely) sO2(OH)2sup>− (example: andyrobertsite). Arsenite minerals are much less common. Both the Dana and the Strunz mineral classifications place the arsenates in with the phosphate minerals. Example arsenate minerals include: *Annabergite Ni3(AsO4)2·8H2O *Austinite CaZn(AsO4)(OH) *Clinoclase Cu3(AsO4)(OH)3 *Conichalcite CaCu(AsO4)(OH) *Cornubite Cu5(AsO4)2(OH)4 *Cornwallite Cu2+5(AsO4)2(OH)2 *Erythrite Co3(AsO4)2·8H2O *Mimetite Pb5(AsO4)3Cl *Olivenite Cu2(AsO4)OH Nickel–Strunz Classification -08- Phosphates IMA-CNMNC proposes a new hierarchical scheme (Mills et al., 2009). This list uses it to modify the Classification of Nickel–Strunz ( mindat.org, 10 ed, pending publication). *Abbreviations: **"*" - discredited ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redox
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. There are two classes of redox reactions: * ''Electron-transfer'' – Only one (usually) electron flows from the reducing agent to the oxidant. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * ''Atom transfer'' – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidation reactions are commonly associated with the formation of oxides, other chemical species can serve the same function. In hydrogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Minerals
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin ''calx'' "lime", which was obtained from heating limestone. Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in foods and pharmace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keweenaw County, Michigan
Keweenaw County (, ; , ) is a county in the Upper Peninsula of the U.S. state of Michigan, the state's northernmost county. As of the 2020 United States Census, the population was 2,046, making it Michigan's least populous county. It is also the state's largest county by total area, when the waters of Lake Superior are included in the total. The county seat is Eagle River. The county was set off and organized in 1861. It is believed "Keweenaw" is a corruption of an Ojibwe word that means "portage" or "place where portage is made"; compare the names of the nearby Portage Lake and Portage River which together make up the Keweenaw Waterway. Keweenaw County is part of the Houghton, Michigan, Micropolitan Statistical Area. Isle Royale, a national park which no longer has year-round inhabitants, was a separate county that was incorporated into Keweenaw County in 1897. Geography Two land masses comprise most of the land portion of the county: Isle Royale and the northeastern half ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morocco
Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to the east, and the disputed territory of Western Sahara to the south. Mauritania lies to the south of Western Sahara. Morocco also claims the Spanish exclaves of Ceuta, Melilla and Peñón de Vélez de la Gomera, and several small Spanish-controlled islands off its coast. It spans an area of or , with a population of roughly 37 million. Its official and predominant religion is Islam, and the official languages are Arabic and Berber; the Moroccan dialect of Arabic and French are also widely spoken. Moroccan identity and culture is a mix of Arab, Berber, and European cultures. Its capital is Rabat, while its largest city is Casablanca. In a region inhabited since the Paleolithic Era over 300,000 years ago, the first Moroccan s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated between the Baltic and North seas to the north, and the Alps to the south; it covers an area of , with a population of almost 84 million within its 16 constituent states. Germany borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The nation's capital and most populous city is Berlin and its financial centre is Frankfurt; the largest urban area is the Ruhr. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before AD 100. In 962, the Kingdom of Germany formed the bulk of the Holy Roman Empire. During the 16th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesse
Hesse (, , ) or Hessia (, ; german: Hessen ), officially the State of Hessen (german: links=no, Land Hessen), is a States of Germany, state in Germany. Its capital city is Wiesbaden, and the largest urban area is Frankfurt. Two other major historic cities are Darmstadt and Kassel. With an area of 21,114.73 square kilometers and a population of just over six million, it ranks seventh and fifth, respectively, among the sixteen German states. Frankfurt Rhine-Main, Germany's second-largest metropolitan area (after Rhine-Ruhr), is mainly located in Hesse. As a cultural region, Hesse also includes the area known as Rhenish Hesse (Rheinhessen) in the neighbouring state of Rhineland-Palatinate. Name The German name '':wikt:Hessen#German, Hessen'', like the names of other German regions (''Schwaben'' "Swabia", ''Franken'' "Franconia", ''Bayern'' "Bavaria", ''Sachsen'' "Saxony"), derives from the dative plural form of the name of the inhabitants or German tribes, eponymous tribe, the Hes ... [...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] |
Erythrite
Erythrite or red cobalt is a secondary hydrated cobalt arsenate mineral with the formula . Erythrite and annabergite, chemical formula , or nickel arsenate form a complete series with the general formula . Erythrite crystallizes in the monoclinic system and forms prismatic crystals. The color is crimson to pink and occurs as a secondary coating known as ''cobalt bloom'' on cobalt arsenide minerals. Well-formed crystals are rare, with most of the mineral manifesting in crusts or small reniform aggregates. Erythrite was first described in 1832 for an occurrence in Grube Daniel, Schneeberg, Saxony, and takes its name from the Greek έρυθρος (''erythros''), meaning red. Historically, erythrite itself has not been an economically important mineral, but the prospector may use it as a guide to associated cobalt and native silver. Erythrite occurs as a secondary mineral in the oxide zone of Co–Ni–As bearing mineral deposits. It occurs in association with cobaltite, skutterud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picropharmacolite
Picropharmacolite, Ca4Mg(AsO3OH)2(AsO4)2·11H2O, is a rare arsenate mineral. It was named in 1819 from the Greek for bitter, in allusion to its magnesium content, and its chemical similarity to pharmacolite. The mineral irhtemite, Ca4Mg(AsO3OH)2(AsO4)2·4H2O, has the same composition as picropharmacolite, except that it has only four water molecules per formula unit, instead of eleven. It may be formed by the dehydration of picropharmacolite. Structure Infrared spectraAmerican Mineralogist (1974) 59:807 show that picropharmacolite contains water molecules H2O, hydroxyl groups (OH)− co-ordinated with Mg2+ cations, and acid arsenate radicals (HAsO4)2−. There are strong structural similarities with guerinite, Ca5(AsO3OH)2(AsO4)2.9H2O which indicates a similar formula for the two minerals.American Mineralogist (1976) 61:326 X-ray diffraction methods indicate that As, Ca and Mg cations are positioned in corrugated layers parallel to the c axis, the layers being linked by h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
