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Vug
A vug, vugh, or vugg () is a small- to medium-sized cavity inside rock. It may be formed through a variety of processes. Most commonly, cracks and fissures opened by tectonic activity ( folding and faulting) are partially filled by quartz, calcite, and other secondary minerals. Open spaces within breccias formed by an ancient collapse are another important source of vugs. Vugs may also form when mineral crystals or fossils inside a rock matrix are later removed through erosion or dissolution processes, leaving behind irregular voids. The inner surfaces of such vugs are often coated with a crystal druse. Fine crystals are often found in vugs where the open space allows the free development of external crystal form. The term ''vug'' is not applied to veins and fissures that have become completely filled, but may be applied to any small cavities within such veins. Geodes are a vug-formed rock, although that term is usually reserved for more rounded crystal-lined cavities in sed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornwall
Cornwall (; or ) is a Ceremonial counties of England, ceremonial county in South West England. It is also one of the Celtic nations and the homeland of the Cornish people. The county is bordered by the Atlantic Ocean to the north and west, Devon to the east, and the English Channel to the south. The largest urban area is the Redruth and Camborne conurbation. The county is predominantly rural, with an area of and population of 568,210. After the Redruth-Camborne conurbation, the largest settlements are Falmouth, Cornwall, Falmouth, Penzance, Newquay, St Austell, and Truro. For Local government in England, local government purposes most of Cornwall is a Unitary authorities of England, unitary authority area, with the Isles of Scilly governed by a Council of the Isles of Scilly, unique local authority. The Cornish nationalism, Cornish nationalist movement disputes the constitutional status of Cornwall and seeks greater autonomy within the United Kingdom. Cornwall is the weste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyromorphite
Pyromorphite is a mineral species composed of lead chlorophosphate: Pb5( P O4)3 Cl, sometimes occurring in sufficient abundance to be mined as an ore of lead. Crystals are common, and have the form of a hexagonal prism terminated by the basal planes, sometimes combined with narrow faces of a hexagonal pyramid. Crystals with a barrel-like curvature are not uncommon. Globular and reniform masses are also found. Pyromorphite is part of the apatite group of minerals and bears a close resemblance physically and chemically with two other minerals: mimetite (Pb5( AsO4)3Cl) and vanadinite (Pb5( VO4)3Cl). The resemblance in external characters is so close that, as a rule, it is only possible to distinguish between them by chemical tests. They were formerly confused under the names green lead ore and brown lead ore (''German: Grünbleierz and Braunbleierz''). History The mineral was first distinguished chemically by M. H. Klaproth in 1784, and it was named pyromorphite by J. F. L. H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heulandite
Heulandite is the name of a series of tectosilicate minerals of the zeolite group. Prior to 1997, heulandite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a series name, with the mineral species being named: * Heulandite-Ca * Heulandite-Na * Heulandite-K * Heulandite-Sr * Heulandite-Ba (described in 2002). Heulandite-Ca, the most common of these, is a hydrous calcium and aluminium silicate with the formula . Small amounts of sodium and potassium are usually present replacing part of the calcium. Strontium replaces calcium in the heulandite-Sr variety. The appropriate species name depends on the dominant element. The species are visually indistinguishable, and the series name heulandite is still used whenever testing has not been performed. Crystallography and properties Crystals are monoclinic. They may have a characteristic coffin-shaped habit, but may also form simple rhombic prisms. Freque ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Druse (geology)
In geology and mineralogy, druse is a crystal habit represented by the coating of fine crystals on a rock (geology), rock fracture (geology), fracture surface, or vein (geology), vein or within a vug or geode. See also * Miarolitic cavity References Mineral habits {{petrology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wulfenite
Wulfenite is a lead molybdate mineral with the formula Pb Mo O4. It often occurs as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is sometimes called "yellow lead ore". It crystallizes in the tetragonal system, often occurring as stubby, pyramidal or tabular crystals. It also occurs as earthy, granular masses. It is found in many localities, associated with lead ores as a secondary mineral associated with the oxidized zone of lead deposits. It is also a secondary ore of molybdenum, and is sought by collectors. Discovery and occurrence Wulfenite was first described in 1845 for an occurrence in Bad Bleiberg, Carinthia, Austria. It was named for Franz Xaver von Wulfen (1728–1805), an Austrian mineralogist. It occurs as a secondary mineral in oxidized hydrothermal lead deposits. It occurs with cerussite, anglesite, smithsonite, hemimorphite, vanadinite, pyromorph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fracture in the Crust (geology), crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is often also called ''lava''. A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.) The viscosity of most lava is about that of ketchup, roughly 10,000 to 100,000 times that of water. Even so, lava can flow great distances before cooling causes it to solidify, because lava exposed to air quickly develops a solid crust that insulates the remaining liquid lava, helping to keep it hot and inviscid enough to continue flowing. Etymology The word ''lava'' comes from Ital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock (geology)
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition, and the way in which it is formed. Rocks form the Earth's outer solid layer, the Earth's crust, crust, and most of its interior, except for the liquid Earth's outer core, outer core and pockets of magma in the asthenosphere. The study of rocks involves multiple subdisciplines of geology, including petrology and mineralogy. It may be limited to rocks found on Earth, or it may include planetary geology that studies the rocks of other celestial objects. Rocks are usually grouped into three main groups: igneous rocks, sedimentary rocks and metamorphic rocks. Igneous rocks are formed when magma cools in the Earth's crust, or lava cools on the ground surface or the seabed. Sedimentary rocks are formed by diagenesis and lithification of sediments, which in turn are formed by the weathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rosasite
Rosasite is a carbonate mineral with minor potential for use as a zinc and copper ore. Chemically, it is a copper zinc carbonate hydroxide with a copper to zinc ratio of 3:2, occurring in the secondary oxidation zone of copper-zinc deposits. It was originally discovered in 1908 in the Rosas mine in Sardinia, Italy, and is named after the location. Fibrous blue-green rosasite crystals are usually found in globular aggregates, often associated with red limonite and other colorful minerals. It is very similar to aurichalcite Aurichalcite is a carbonate mineral, usually found as a secondary mineral in copper and zinc deposits. Its chemical formula is . The zinc to copper ratio is about 5:4. Copper (Cu2+) gives aurichalcite its green-blue colors. Occurrence Aurichalci ..., but can be distinguished by its superior hardness. References Mineral galleries Copper(II) minerals Zinc minerals Carbonate minerals Monoclinic minerals Minerals in space group 14 Minerals described in 1908< ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fissure
A fissure is a long, narrow crack opening along the surface of Earth. The term is derived from the Latin word , which means 'cleft' or 'crack'. Fissures emerge in Earth's crust, on ice sheets and glaciers, and on volcanoes. Ground fissure A , also called an , is a long, narrow crack or linear opening in the Earth's crust. Ground fissures can form naturally, such as from tectonic faulting and earthquakes, or as a consequence of human activity, such as oil mining and groundwater pumping. Once formed, ground fissures can be extended and eroded by torrential rain. They can be hazardous to people and livestock living on the affected surfaces and damaging to property and infrastructure, such as roads, underground pipes, canals, and dams. In circumstances where there is the extensive withdrawal of groundwater, the earth above the water table can subside causing fissures to form at the surface. This typically occurs at the floor of arid valleys having rock formations and compact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azurite
Azurite or '' Azure spar''''Krivovichev V. G.'' Mineralogical glossary. Scientific editor A. G. Bulakh. — St.Petersburg: St.Petersburg Univ. Publ. House. 2009. — 556 p. — ISBN 978-5-288-04863-0. ''(in Russian)'' is a soft, deep-blue copper mineral produced by weathering of copper ore deposits. During the early 19th century, it was also known as chessylite, after the type locality at Chessy-les-Mines near Lyon, France. The mineral, a basic carbonate with the chemical formula Cu3(CO3)2(OH)2, has been known since ancient times, and was mentioned in Pliny the Elder's '' Natural History'' under the Greek name (κυανός: "deep blue," root of English cyan) and the Latin name '' caeruleum''. Copper (Cu2+) gives it its blue color. Mineralogy Azurite has the formula Cu3(CO3)2(OH)2, with the copper(II) cations linked to two different anions, carbonate and hydroxide. It is one of two relatively common basic copper(II) carbonate minerals, the other being bright green malach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
