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Hardin County, Illinois
Hardin County is a county located in the U.S. state of Illinois. According to the 2020 census, it has a population of 3,649, making it the least populous county in Illinois. Its county seat is Elizabethtown. Hardin County is located in the part of the state known as Little Egypt. Hardin County was named for Hardin County, Kentucky, which was named in honor of Colonel John Hardin, an officer in the American Revolutionary War and the Northwest Indian War. History Hardin County was formed in 1839 from Pope County. Additional area was later added from Gallatin County. Hardin County was named for Hardin County, Kentucky, which was named in honor of Colonel John Hardin, an officer in the American Revolutionary War and the Northwest Indian War. Hardin was murdered by Shawnee Indians while he was on a peace mission in 1792 for President George Washington, in what is now Shelby County, Ohio. In the 1790s and early 1800s, the Hardin County area, especially Cave-In-Rock, was noto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardin County Courthouse (Illinois)
The Hardin County Courthouse is a government building in Elizabethtown, the county seat of Hardin County, Illinois, United States. Built in 1927, it is the fourth building to serve this purpose in Hardin County, following three that were replaced due to fires or fire-related concerns. History As late as the beginning of the 19th century, today's Hardin County was a debatable and deserted land; the advance of civilization was held back by perennial conflict among the Indians of the region;The Historical Committee for the Centennial. History of Hardin County, Illinois'. N.pl.: The Committee, 1939. the earliest residents of the county were squatters, as no land offices existed in the area until one was opened at Shawneetown in 1814. Even after the opening of the land office, surveying was limited, and the area's first firm county boundaries were enacted upon the formation of Hardin County in 1839. The county's obscure first courthouse was a wooden building, and the danger of fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shelby County, Ohio
Shelby County is a county in the western portion of the U.S. state of Ohio. As of the 2020 United States Census, the population was 48,230. Its county seat is Sidney. Its name honors Isaac Shelby, first governor of Kentucky. Shelby County comprises the Sidney, OH Micropolitan Statistical Area, which is also included in the Dayton-Springfield-Sidney, OH Combined Statistical Area. History The Algonquian-speaking Shawnee Native Americans had come into the area in the 18th century, displacing the Ojibwa-speaking Ottawa of the Anishinaabeg, a related language group who moved northwest. The Shawnee were joined by the Iroquois, Seneca and Mingo peoples as well, displaced by colonial encroachment to the east. In 1792 the European-American pioneer John Hardin was killed by the Shawnee in Shelby County. Early settlers named the first county seat of Hardin in his memory. Shelby County was created in 1819 from Miami County. Its original boundary included Minster and New Bremen; thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Union County, Kentucky
Union County is a county in the U.S. state of Kentucky. As of the 2020 United States census, the population was 13,668. Its county seat is Morganfield. The county was created effective January 15, 1811. The county is located on the left (east) bank of the Ohio River opposite its confluence with the Wabash River. Union County, along with neighboring Posey County, Indiana, and Gallatin County, Illinois, form the tri-point of the Illinois-Indiana-Kentucky Tri-State Area. Geography Union County lies on the northern border of Kentucky; its northwestern border is formed by the meanders of the Ohio River, abutting the states of Illinois and Indiana. The county terrain consists of frequent low wooded hills among the level areas, which are devoted to agriculture. Its highest point ( ASL) is a rise in the Chalybeate Hills, in the Higginson-Henry Wildlife Management Area. The John T. Myers Locks and Dam, authorized and constructed as Uniontown Locks and Dam, is located downstream from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Fluoride
Calcium fluoride is the inorganic compound of the elements calcium and fluorine with the formula CaF2. It is a white insoluble solid. It occurs as the mineral fluorite (also called fluorspar), which is often deeply coloured owing to impurities. Chemical structure The compound crystallizes in a cubic motif called the fluorite structure. Ca2+ centres are eight-coordinate, being centered in a cube of eight Fâ centres. Each Fâ centre is coordinated to four Ca2+ centres in the shape of a tetrahedron. Although perfectly packed crystalline samples are colorless, the mineral is often deeply colored due to the presence of F-centers. The same crystal structure is found in numerous ionic compounds with formula AB2, such as CeO2, cubic ZrO2, UO2, ThO2, and PuO2. In the corresponding anti-structure, called the antifluorite structure, anions and cations are swapped, such as Be2C. Gas phase The gas phase is noteworthy for failing the predictions of VSEPR theory; the molecule is no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorspar
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 4 as fluorite. Pure fluorite is colourless and transparent, both in visible and ultraviolet light, but impurities usually make it a colorful mineral and the stone has ornamental and lapidary uses. Industrially, fluorite is used as a flux for smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture, which is the intermediate source of most fluorine-containing fine chemicals. Optically clear transparent fluorite lenses have low dispersion, so lenses made from it exhibit less chromatic aberration, making them valuable in microscopes and telescopes. Fluorite optics are also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorine
Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reactive, as it reacts with all other elements except for the light inert gases. Among the elements, fluorine ranks 24th in universal abundance and 13th in terrestrial abundance. Fluorite, the primary mineral source of fluorine which gave the element its name, was first described in 1529; as it was added to metal ores to lower their melting points for smelting, the Latin verb meaning 'flow' gave the mineral its name. Proposed as an element in 1810, fluorine proved difficult and dangerous to separate from its compounds, and several early experimenters died or sustained injuries from their attempts. Only in 1886 did French chemist Henri Moissan isolate elemental fluorine using low-temperature electrolysis, a process still employed for modern pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Pipe
Volcanic pipes or volcanic conduits are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. They are considered to be a type of ''diatreme''. Volcanic pipes are composed of a deep, narrow cone of solidified magma (described as "carrot-shaped"), and are usually largely composed of one of two characteristic rock types â kimberlite or lamproite. These rocks reflect the composition of the volcanoes' deep magma sources, where the Earth is rich in magnesium. Volcanic pipes are relatively rare. They are well known as the primary source of diamonds, and are mined for this purpose. Formation Volcanic pipes form as the result of violent eruptions of deep-origin volcanoes. These volcanoes originate at least three times as deep as most other volcanoes, and the resulting magma that is pushed toward the surface is high in magnesium and volatile compounds such as water and carbon dioxide. As the body of magma rises toward the surface, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breccia
Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia, tectonic breccia, igneous breccia, impact breccia, and hydrothermal breccia. A megabreccia is a breccia composed of very large rock fragments, sometimes kilometers across, which can be formed by landslides, impact events, or caldera collapse. Types Breccia is composed of coarse rock fragments held together by cement or a fine-grained matrix. Like conglomerate, breccia contains at least 30 percent of gravel-sized particles (particles over 2mm in size), but it is distinguished from conglomerate because the rock fragments have sharp edges that have not been worn down. These indicate that the gravel was deposited very close to its source area, since otherwise th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diatreme
A diatreme, sometimes known as a maar-diatreme volcano, is a volcanic pipe formed by a gaseous explosion. When magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ... rises up through a crack in Earth's crust and makes contact with a shallow body of groundwater, rapid expansion of heated water vapor and volcanic gases can cause a series of explosions. A relatively shallow crater (known as a ''maar'') is left, and a rock-filled fracture (the actual diatreme) in the crust. Diatremes breach the surface and produce a steep, inverted cone shape. The term ''diatreme'' has been applied more generally to any concave body of broken rock formed by explosive or hydrostatics, hydrostatic forces, whether or not it is related to volcanism. The word comes . Global distribution Maar-diatreme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igneous Rock
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main The three types of rocks, rock types, the others being Sedimentary rock, sedimentary and metamorphic rock, metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from Partial melting, partial melts of existing rocks in either a Terrestrial planet, planet's mantle (geology), mantle or crust (geology), crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive (geology), extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form Volcanic glass, natural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultramafic Rock
Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed of usually greater than 90% mafic minerals (dark colored, high magnesium and iron content). The Earth's mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks. Intrusive ultramafic rocks Intrusive ultramafic rocks are often found in large, layered ultramafic intrusions where differentiated rock types often occur in layers. Such cumulate rock types do not represent the chemistry of the magma from which they crystallized. The ultramafic intrusives include the dunites, peridotites and pyroxenites. Other rare varieties include troctolite which has a greater percentag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Census Bureau
The United States Census Bureau (USCB), officially the Bureau of the Census, is a principal agency of the U.S. Federal Statistical System, responsible for producing data about the American people and economy. The Census Bureau is part of the U.S. Department of Commerce and its director is appointed by the President of the United States. The Census Bureau's primary mission is conducting the U.S. census every ten years, which allocates the seats of the U.S. House of Representatives to the states based on their population. The bureau's various censuses and surveys help allocate over $675 billion in federal funds every year and it assists states, local communities, and businesses make informed decisions. The information provided by the census informs decisions on where to build and maintain schools, hospitals, transportation infrastructure, and police and fire departments. In addition to the decennial census, the Census Bureau continually conducts over 130 surveys and programs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
