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Crocoite
Crocoite is a mineral consisting of lead chromate, Pb Cr O4, and crystallizing in the monoclinic crystal system. It is identical in composition with the artificial product chrome yellow used as a paint pigment. Description Crocoite is commonly found as large, well-developed prismatic adamantine crystals, although in many cases are poorly terminated. Crystals are of a bright hyacinth-red color, translucent, and have an adamantine to vitreous lustre. On exposure to UV light some of the translucency and brilliancy is lost. The streak is orange-yellow; Mohs hardness is 2.5–3; and the specific gravity is 6.0. It was discovered at the Berezovskoe Au Deposit (Berezovsk Mines) near Ekaterinburg in the Urals in 1766; and named crocoise by F. S. Beudant in 1832, from the Greek κρόκος (''krokos''), saffron, in allusion to its color, a name first altered to crocoisite and afterwards to crocoite. In the type locality the crystals are found in gold-bearing quartz-veins traver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocoite Crystal Structure
Crocoite is a mineral consisting of lead chromate, Pb Cr O4, and crystallizing in the monoclinic crystal system. It is identical in composition with the artificial product chrome yellow used as a paint pigment. Description Crocoite is commonly found as large, well-developed prismatic adamantine crystals, although in many cases are poorly terminated. Crystals are of a bright hyacinth-red color, translucent, and have an adamantine to vitreous lustre. On exposure to UV light some of the translucency and brilliancy is lost. The streak is orange-yellow; Mohs hardness is 2.5–3; and the specific gravity is 6.0. It was discovered at the Berezovskoe Au Deposit (Berezovsk Mines) near Ekaterinburg in the Urals in 1766; and named crocoise by F. S. Beudant in 1832, from the Greek κρόκος (''krokos''), saffron, in allusion to its color, a name first altered to crocoisite and afterwards to crocoite. In the type locality the crystals are found in gold-bearing quartz-veins traversin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium
Chromium is a chemical element; it has Symbol (chemistry), symbol Cr and atomic number 24. It is the first element in Group 6 element, group 6. It is a steely-grey, Luster (mineralogy), lustrous, hard, and brittle transition metal. Chromium is valued for its high corrosion resistance and hardness. A major development in steel production was the discovery that steel could be made highly resistant to corrosion and discoloration by adding metallic chromium to form stainless steel. Stainless steel and chrome plating (electroplating with chromium) together comprise 85% of the commercial use. Chromium is also greatly valued as a metal that is able to be highly polishing, polished while resisting tarnishing. Polished chromium reflects almost 70% of the visible spectrum, and almost 90% of infrared, infrared light. The name of the element is derived from the Ancient Greek, Greek word χρῶμα, ''chrōma'', meaning color, because many chromium compounds are intensely colored. Indust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Chromate
Lead(II) chromate is an inorganic compound with the chemical formula . It is a bright yellow salt that is very poorly soluble in water. It occurs also as the mineral crocoite. It is used as a pigment. Structure Two polymorphs of lead chromate are known, orthorhombic and the more stable monoclinic form. Monoclinic lead chromate is used in paints under the name chrome yellow, and many other names. Lead chromate adopts the monazite structure, meaning that the connectivity of the atoms is very similar to other compounds of the type . Pb(II) has a distorted coordination sphere being surrounded by eight oxides with Pb-O distances ranging from 2.53 to 2.80 Å. The chromate anion is tetrahedral, as usual. Unstable polymorphs of lead chromate are the greenish yellow orthorhombic form and a red-orange tetragonal form. Applications Approximately 37,000 tons were produced in 1996. The main applications are as a pigment in paints, under the name chrome yellow. Preparation Lead(II ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Nicolas Vauquelin
Louis Nicolas Vauquelin FRS(For) HFRSE (; 16 May 1763 – 14 November 1829) was a French pharmacist and chemist. He was the discoverer of chromium and beryllium. Early life Vauquelin was born at Saint-André-d'Hébertot in Normandy, France, the son of Nicolas Vauquelin, an estate manager, and his wife, Catherine Le Charterier. His first acquaintance with chemistry was gained as laboratory assistant to an apothecary in Rouen (1777–1779), and after various vicissitudes he obtained an introduction to A. F. Fourcroy, in whose laboratory he was an assistant from 1783 to 1791. Moving to Paris, he became a laboratory assistant at the Jardin du Roi and was befriended by a professor of chemistry. In 1791 he was made a member of the Academy of Sciences and from that time he helped to edit the journal '' Annales de Chimie'' ''(Chemical annals)'', although he left the country for a while during the height of the French Revolution. In 1798 Vauquelin discovered beryllium oxide by extrac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromite
Chromite is a crystalline mineral composed primarily of iron(II) oxide and chromium(III) oxide compounds. It can be represented by the chemical formula of Iron, FeChromium, Cr2Oxygen, O4. It is an oxide mineral belonging to the spinel group. The element magnesium can substitute for iron in variable amounts as it forms a solid solution with magnesiochromite (Magnesium, MgChromium, Cr2Oxygen, O4). Substitution of the element aluminium can also occur, leading to hercynite (Iron, FeAluminum, Al2Oxygen, O4). Chromite today is mined particularly to make stainless steel through the production of ferrochrome (Iron, FeChromium, Cr), which is an iron-chromium alloy. Chromite grains are commonly found in large mafic igneous intrusions such as the Bushveld in South Africa and India. Chromite is iron-black in color with a metallic Lustre (mineralogy), luster, a dark brown Streak (mineralogy), streak and a hardness on the Mohs scale of mineral hardness, Mohs scale of 5.5. Properties Chromite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dundas, Tasmania
Dundas was a historical mining locality, mineral field and railway location on the western foothills of the West Coast Range in Western Tasmania. It is now part of the locality of Zeehan. Location The town was located 5 kilometres east of the town of Zeehan, and almost 10 kilometres west of the Mount Read township. The North East Dundas Tram branched off the Emu Bay Railway approximately 3 kilometres north east of the Dundas railway connection. The location was hilly and heavily wooded, making the location hazardous in the event of bushfires. The location, being close to Mount Read, was also prone to heavy rain and cold weather. Mount Dundas Post Office was opened on 22 November 1890, renamed ''Dundas'' in 1892 and closed in 1930. The '' Zeehan and Dundas Herald'' (1902–1922) was one of the more significant newspapers of the west coast during its operation. Mines and minerals Silver was discovered early in the Dundas area in 1890, and the name of the Dundas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vauquelinite
Vauquelinite is a complex mineral with the formula Cu Pb2( Cr O4)( PO4)(O H) making it a combined chromate and phosphate of copper and lead. It forms a series with the arsenate mineral fornacite. It was first described in 1818 in the Beryozovskoye deposit, Urals, Russia, and named for Louis Vauquelin (1763–1829), a French chemist. It occurs in oxidized hydrothermal ore deposits and is associated with crocoite, pyromorphite, mimetite, cerussite, beudantite Beudandite is a secondary mineral occurring in the Oxidation, oxidized zones of Polymetal, polymetallic deposits. It is a lead, iron, Arsenate mineral, arsenate, sulfate mineral, sulfate with Chemical formula, endmember formula: PbFe3(OH)6SO4AsO4 ... and duftite at the type locality in Russia. References Copper(II) minerals Lead minerals Chromate minerals Phosphate minerals Monoclinic minerals Minerals in space group 14 {{phosphate-mineral-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chrome Yellow
Chrome yellow is a bright, warm yellow pigment that has been used in art, fashion, and industry. It is the premier orange pigment for many applications. Production of chrome yellow and related pigments The raw pigment precipitates as a fine solid upon mixing lead(II) salts and a source of chromate. Approximately 90,000 tons of chrome yellow are produced annually as of 2001. Chrome yellow pigments are usually encapsulated by coating with transparent oxides that protect the pigment from environmental factors that would diminish their colorant properties. Related lead sulfochromate pigments are produced by the replacement of some chromate by sulfate, resulting in a mixed lead-chromate-sulfate compositions Pb(CrO4)1-x(SO4)x. This replacement is possible because sulfate and chromate are isostructural. Since sulfate is colorless, sulfochromates with high values of x are less intensely colored than lead chromate. In some cases, chromate is replaced by molybdate. Permanence Chro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromate Minerals
Chromate or chromat, and their derived terms, may refer to: Chemistry * Chromate and dichromate, ions * Monochromate, an ion *Trichromate, an ion *Tetrachromate, an ion * Chromate conversion coating, a method for passivating metals Biology *Monochromacy (monochromate) having one color vision *Dichromatism (dichromate) having two color vision *Trichromacy (trichromate) having three color vision *Trichrome staining, a staining method *Tetrachromacy (tetrachromate) having four color vision Other *Chromat, a fashion label *Monochromatic or monochrome, images composed of one color (or values of one color) See also *Chromite, a chromium-containing mineral *Chromite (compound), chemical compounds containing the (CrO2)− anion *Chrome (other) {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gneiss
Gneiss (pronounced ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under pressures ranging from 2 to 15 kbar, sometimes even more, and temperatures over 300 °C (572 °F). Gneiss nearly always shows a banded texture characterized by alternating darker and lighter colored bands and without a distinct Cleavage (geology), cleavage. Gneisses are common in the ancient crust of Continental Shield, continental shields. Some of the oldest rocks on Earth are gneisses, such as the Acasta Gneiss. Description image:Orthogneiss Geopark.jpg, Orthogneiss from the Czech Republic In traditional English and North American usage, a gneiss is a coarse-grained metamorphic rock showing compositional banding (gneissic banding) but poorly developed schistosity and indistinct Cleavage (geology), cleavage. In other words, it i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phoenicochroite
Phoenicochroite, also known as melanochroite, is a lead chromate mineral with formula Pb2OCrO4. It forms striking orange red crystals. It was first discovered in 1839 in Beryozovskoye deposit, Urals, Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders .... It is named from the Greek word φοίυικος for "deep red" and χρόα for "color", in allusion to its color. References Lead minerals Chromate minerals Monoclinic minerals Minerals in space group 12 {{Mineral-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brazil
Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population, seventh-largest by population, with over 212 million people. The country is a federation composed of 26 Federative units of Brazil, states and a Federal District (Brazil), Federal District, which hosts the capital, Brasília. List of cities in Brazil by population, Its most populous city is São Paulo, followed by Rio de Janeiro. Brazil has the most Portuguese-speaking countries, Portuguese speakers in the world and is the only country in the Americas where Portuguese language, Portuguese is an Portuguese-speaking world, official language. Bounded by the Atlantic Ocean on the east, Brazil has a Coastline of Brazil, coastline of . Covering roughly half of South America's land area, it Borders of Brazil, borders all other countries and ter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
