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Acanthite
Acanthite is a form of silver sulfide with the chemical formula Ag2S. It crystallizes in the monoclinic system and is the stable form of silver sulfide below . Argentite is the stable form above that temperature. As argentite cools below that temperature its cubic form is distorted to the monoclinic form of acanthite. Below 173 °C acanthite forms directly. Acanthite is the only stable form in normal air temperature. Occurrence Acanthite is a common silver mineral in moderately low-temperature hydrothermal veins and in zones of supergene enrichment. It occurs in association with native silver, pyrargyrite, proustite, polybasite, stephanite, aguilarite, galena, chalcopyrite, sphalerite, calcite and quartz. Acanthite was first described in 1855 for an occurrence in the Jáchymov (St Joachimsthal) District, Krušné Hory Mts ( Erzgebirge), Karlovy Vary Region, Bohemia, Czech Republic. The name is from the Greek "akantha" meaning thorn or arrow, in reference to its cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aguilarite
Aguilarite is an uncommon sulfosalt mineral with formula Ag4 Se S. It was described in 1891 and named for discoverer Ponciano Aguilar. Description Aguilarite is bright lead-gray on fresh surfaces but becomes dull iron black when exposed to air. The mineral occurs with massive habit, as elongated pseudododecahedral crystals up to , or as intergrowths with acanthite or naumannite. Discovery In the late 19th century, Ponciano Aguilar, superintendent of the San Carlos mine in Guanajuato, Mexico, found several specimens of a mineral thought to be naumannite. The samples were given to F. A. Genth for identification, who, along with S. L. Penfield, discovered that it was a new mineral. The mineral was described in the ''American Journal of Science'' in 1891 and named ''aguilarite'' in honor of Ponciano Aguilar. When the International Mineralogical Association was founded, aguilarite was grandfathered as a valid mineral species. Occurrence Aguilarite is uncommon, and forms at relat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver Sulfide
Silver sulfide is an inorganic compound with the formula . A dense black solid, it is the only sulfide of silver. It is useful as a photosensitizer in photography. It constitutes the tarnish that forms over time on silverware and other silver objects. Silver sulfide is insoluble in most solvents, but is degraded by strong acids. Silver sulfide is a network solid made up of silver (electronegativity of 1.98) and sulfur (electronegativity of 2.58) where the bonds have low ionic character (approximately 10%). Formation Silver sulfide naturally occurs as the tarnish on silverware. When combined with silver, hydrogen sulfide gas creates a layer of black silver sulfide patina on the silver, protecting the inner silver from further conversion to silver sulfide. Silver whiskers can form when silver sulfide forms on the surface of silver electrical contacts operating in an atmosphere rich in hydrogen sulfide and high humidity. Such atmospheres can exist in sewage treatment and paper mil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentite
In mineralogy, argentite (from the Latin ''argentum'', silver) is cubic silver sulfide (Ag2S), which can only exist at temperatures above 173 °C, 177 °C or 179 °C. When it cools to ordinary temperatures it turns into its monoclinic polymorph, acanthite. The International Mineralogical Association has decided to reject argentite as a proper mineral. The name "argentite" sometimes also refers to pseudomorphs of argentite: specimens of acanthite which still display some of the outward signs of the cubic crystal form, even though their actual crystal structure is monoclinic due to the lower temperature. This form of acanthite is occasionally found as uneven cubes and octahedra, but more often as dendritic or earthy masses, with a blackish lead-grey color and metallic luster. Argentite belongs to the galena group. Cleavage, which is so prominent a feature in galena, here presents only in traces. The mineral is perfectly sectile and has a shining streak; hardness 2. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver Minerals
Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earth's crust in the pure, free elemental form ("native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining. Silver has long been valued as a precious metal. Silver metal is used in many bullion coins, sometimes alongside gold: while it is more abundant than gold, it is much less abundant as a native metal. Its purity is typically measured on a per-mille basis; a 94%-pure alloy is described as "0.940 fine". As one of the seven metals of antiquity, silver has had an enduring role in most human cultures. Other than in curre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proustite
Proustite is a sulfosalt mineral consisting of silver sulfarsenide, Ag3 As S3, known also as light red silver or ruby silver ore, and an important source of the metal. It is closely allied to the corresponding sulfantimonide, pyrargyrite, from which it was distinguished by the chemical analyses of Joseph L. Proust (1754–1826) in 1804, after whom the mineral received its name. The prismatic crystals are often terminated by the scalenohedron and the obtuse rhombohedron, thus resembling calcite (dog-tooth-spar) in habit. The color is scarlet-vermilion and the luster adamantine; crystals are transparent and very brilliant, but on exposure to light they soon become dull black and opaque. The streak is scarlet, the hardness 2 to 2.5, and the specific gravity 5.57. Its transparency differs from specimen to specimen, but most are opaque or translucent. Proustite occurs in hydrothermal deposits as a phase in the oxidized and supergene zone. It is associated with other silver miner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephanite
Stephanite is a silver antimony sulfosalt mineral with formula: Ag5 Sb S4. It is composed of 68.8% silver, and sometimes is of importance as an ore of this metal. History Under the name Schwarzerz it was mentioned by Georgius Agricola in 1546, and it has been variously known as "black silver ore" ( German ''Schwarzgultigerz''), brittle silver-ore (''Sprödglanzerz''), etc. The name stephanite was proposed by W Haidinger in 1845 in honour of the Archduke of Austria Stephan Franz Victor of Habsburg-Lorena (1817-1867). French authors use F. S. Beudant's name psaturose (from the Greek ''ψαθυρός'', fragile). Properties It frequently occurs as well-formed crystals, which are orthorhombic and occasionally show indications of hemimorphism: they have the form of six-sided prisms or flat tables terminated by large basal planes and often modified at the edges by numerous pyramid-planes. Twinning on the prism-planes is of frequent occurrence, giving rise to pseudo-hexagonal gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphalerite
Sphalerite (sometimes spelled sphaelerite) is a sulfide mineral with the chemical formula . It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary exhalative, Mississippi-Valley type, and volcanogenic massive sulfide deposits. It is found in association with galena, chalcopyrite, pyrite (and other sulfides), calcite, dolomite, quartz, rhodochrosite, and fluorite. German geologist Ernst Friedrich Glocker discovered sphalerite in 1847, naming it based on the Greek word ''sphaleros'', meaning "deceiving", due to the difficulty of identifying the mineral. In addition to zinc, sphalerite is an ore of cadmium, gallium, germanium, and indium. Miners have been known to refer to sphalerite as ''zinc blende'', ''black-jack'', and ''ruby blende''. Marmatite is an opaque black variety with a high iron content. Crystal habit and structure Sphalerite crystallizes in the face-centered cubic zincblende crystal s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfide Minerals
The sulfide minerals are a class of minerals containing sulfide (S2−) or disulfide (S22−) as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, the sulfarsenides and the sulfosalts.http://www.minerals.net/mineral/sort-met.hod/group/sulfgrp.htm Minerals.net Dana Classification, SulfidesKlein, Cornelis and Cornelius S. Hurlbut, Jr., 1986, ''Manual of Mineralogy'', Wiley, 20th ed., pp 269-293 Sulfide minerals are inorganic compounds. Minerals Common or important examples include: * Acanthite * Chalcocite * Bornite *Galena *Sphalerite *Chalcopyrite *Pyrrhotite * Millerite *Pentlandite * Covellite *Cinnabar * Realgar *Orpiment * Stibnite *Pyrite *Marcasite * Molybdenite Sulfarsenides: * Cobaltite *Arsenopyrite * Gersdorffite Sulfosalts: * Pyrargyrite *Proustite *Tetrahedrite * Tennantite * Enargite * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guanajuato
Guanajuato (), officially the Free and Sovereign State of Guanajuato ( es, Estado Libre y Soberano de Guanajuato), is one of the 32 states that make up the Federal Entities of Mexico. It is divided into 46 municipalities and its capital city is Guanajuato. Guanajuato is in central Mexico. It is bordered by the states of Jalisco to the west, Zacatecas to the northwest, San Luis Potosí to the north, Querétaro to the east, and Michoacán to the south. It covers an area of . The state is home to several historically important cities, especially those along the "Bicentennial Route", which retraces the path of Miguel Hidalgo y Costilla's insurgent army at the beginning of the Mexican War of Independence. This route begins at Dolores Hidalgo, and passes through the Sanctuary of Atotonilco, San Miguel de Allende, Celaya, and the capital of Guanajuato. Other important cities in the state include León, the state's biggest city, Salamanca, and Irapuato. The first town establi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonora
Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. The state is divided into 72 municipalities; the capital (and largest) city of which being Hermosillo, located in the center of the state. Other large cities include Ciudad Obregón, Nogales (on the Mexico-United States border), San Luis Río Colorado, and Navojoa. Sonora is bordered by the states of Chihuahua to the east, Baja California to the northwest and Sinaloa to the south. To the north, it shares the U.S.–Mexico border primarily with the state of Arizona with a small length with New Mexico, and on the west has a significant share of the coastline of the Gulf of California. Sonora's natural geography is divided into three parts: the Sierra Madre Occidental in the east of the state; plains and rolling hills in the center; and the coast on the Gulf of California. It is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arizpe
Arizpe (or Arispe) is a small town and the municipal seat of the Arizpe Municipality in the north of the Mexican state of Sonora. It is located at 30°20'"N 110°09'"W. The area of the municipality is 2,806.78 sq.km. The population in 2005 was 2,959 of which 1,743 lived in the municipal seat as of the 2000 census. History The region of Arizpe was occupied by the Opata people. The name ''Arizpe'' is a Basque word "Aritzpe"(''(H)Aritz'' meaning Oak and ''Pe'' meaning under) and translates to "Under the Oaks". Arizpe was founded in 1646 by the Jesuit missionary Jerónimo de la Canal, with one of the Spanish missions in the Sonoran Desert. Provincias Internas In 1776 Arizpe was made the capital of the Spanish colonial Comandancia y Capitanía General de las Provincias Internas. As the capital, Arizpe became a city by the end of the eighteenth century, the first in the Sonora region. The Provincias Internas had jurisdiction over the provinces of: Sonora and Sinaloa (present ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Czech Republic
The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The Czech Republic has a hilly landscape that covers an area of with a mostly temperate continental and oceanic climate. The capital and largest city is Prague; other major cities and urban areas include Brno, Ostrava, Plzeň and Liberec. The Duchy of Bohemia was founded in the late 9th century under Great Moravia. It was formally recognized as an Imperial State of the Holy Roman Empire in 1002 and became a kingdom in 1198. Following the Battle of Mohács in 1526, the whole Crown of Bohemia was gradually integrated into the Habsburg monarchy. The Protestant Bohemian Revolt led to the Thirty Years' War. After the Battle of White Mountain, the Habsburgs consolidated their rule. With the dissolution of the Holy Empire in 1806, the C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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