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Sunstone
Sunstone is a microcline or oligoclase feldspar, which when viewed from certain directions exhibits a aventurescence, spangled appearance. It has been found in Southern Norway, Sweden, various United States localities and on some beaches along the midcoast of South Australia. Properties Physical properties The optical effect is due to reflections from inclusions of red copper, hematite, or goethite, in the form of minute scales, which are hexagonal, rhombus, rhombic, or irregular in shape, and are disposed parallel to the principal cleavage (crystal), cleavage-plane. These inclusions give the stone an appearance something like that of aventurine, hence sunstone is known also as "aventurine-feldspar". The optical effect is called schiller and the color of Oregon Sunstone is due to copper. The middle part of this crystal sparkles, and usually the color is darkest in the middle and becomes lighter toward the outer edges. The feldspar which usually displays the aventurine appea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plush, Oregon
Plush is an unincorporated rural community and census-designated place in the Warner Valley of Lake County, in the U.S. state of Oregon. As of the 2010 census it had a population of 57. The community is in an arid, sparsely populated part of the state by road northeast of Lakeview. The valley surrounding Plush contains many marshes and shallow lakes, most of them intermittent. Frequented by Native Americans for many thousands of years, the valley became a region of sheep grazing and cattle ranching by the late 19th century. Plush's infrastructure includes a store, an elementary school, and a church. Nearby attractions include Hart Mountain National Antelope Refuge, Warner Wetlands, and the Oregon Sunstone Public Collection Area. History People have lived in the Warner Valley for more than 10,000 years. Evidence of Native American occupation includes petroglyphs, hunting blinds, flakes from obsidian tools, and other material artifacts. By historic times, the Kidüt� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tvedestrand
is List of municipalities of Norway, municipality in Agder counties of Norway, county, Norway. It is located in the Districts of Norway, traditional district of Southern Norway, Sørlandet. The administrative center is the Tvedestrand (town), town of Tvedestrand. There are many villages in the municipality including Dypvåg (village), Dypvåg, Fiane, Tvedestrand, Fiane, Gjeving, Gødderstad, Grønland, Agder, Grønland, Kilen, Tvedestrand, Kilen, Klåholmen, Kråkvåg, Agder, Krokvåg, Laget, Lyngør, Nesgrenda, Østerå, Sagesund, Sandvika, Agder, Sandvika, and Songe. The Tvedestrand (town), town of Tvedestrand has a white-painted town center with irregular streets climbing steep hills around the harbor. The natural environment of the area makes it a tourist destination. The municipality includes numerous islands, which makes it popular in the summer for boaters. The number of people in the municipality practically doubles in the summer, due to vacationers. There are approximat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aventurescence
In gemology, aventurescence (sometimes called aventurization) is an optical reflectance effect seen in certain gems. The effect amounts to a metallic glitter, arising from minute, preferentially oriented mineral platelets within the material. These platelets are so numerous that they also influence the material's body colour. In aventurine quartz, chrome-bearing fuchsite produces a green stone, and various iron oxide An iron oxide is a chemical compound composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Ferric oxyhydroxides are a related class of compounds, perhaps the best known of which is rust. Iron ...s produce a red stone. The words ''aventurine'' and ''aventurescence'' derive from the Italian "a ventura", meaning "by chance". This is an allusion to the chance discovery of aventurine glass (goldstone) at some point in the 18th century. Goldstone is still manufactured today as an artificial imitation of the later d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tectosilicate
Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, the crystalline forms of silica (silicon dioxide, ) are usually considered to be tectosilicates, and they are classified as such in the Dana system (75.1). However, the Nickel-Strunz system classifies them as oxide minerals (4.DA). Silica is found in nature as the mineral quartz, and its polymorphs. On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as a result of the processes that have been forming and re-working the crust for billions of years. These processes include partial melting, crystallization, fractionation, metamorphism, weathering, and diagenesis. Living organisms also contribute to this geologic cycle. For example, a type of plankton known as diatoms construct their exoskeletons ("frustules") from silica extracted from sea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhombus
In plane Euclidean geometry, a rhombus (: rhombi or rhombuses) is a quadrilateral whose four sides all have the same length. Another name is equilateral quadrilateral, since equilateral means that all of its sides are equal in length. The rhombus is often called a "diamond", after the Diamonds (suit), diamonds suit in playing cards which resembles the projection of an Octahedron#Orthogonal projections, octahedral diamond, or a lozenge (shape), lozenge, though the former sometimes refers specifically to a rhombus with a 60° angle (which some authors call a calisson after calisson, the French sweet—also see Polyiamond), and the latter sometimes refers specifically to a rhombus with a 45° angle. Every rhombus is simple polygon, simple (non-self-intersecting), and is a special case of a parallelogram and a Kite (geometry), kite. A rhombus with right angles is a square. Etymology The word "rhombus" comes from , meaning something that spins, which derives from the verb , roman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middletown Township, Delaware County, Pennsylvania
Middletown Township is a township in Delaware County, Pennsylvania, United States. The population was 15,807 at the 2010 census. The Pennsylvania State University has an undergraduate satellite campus called Penn State Brandywine located in the north-central portion of the township. Located outside of Philadelphia, it constitutes part of the Delaware Valley (i.e. the Philadelphia metro area). Originally established in 1686, Middletown Township adopted a Home Rule Charter in 1978. The township is governed by the council-manager system, a representative form of government in which the seven elected officials set policy for the township and the manager oversees the delivery of all public services and programs. History Middletown Township was probably established as a township in 1686, but it is first mentioned in 1687 when John Martin was established as constable. The name of the township is believed to be derived from its position in the middle or center of Chester County where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siberia
Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states since the lengthy conquest of Siberia, which began with the fall of the Khanate of Sibir in 1582 and concluded with the annexation of Chukotka in 1778. Siberia is vast and sparsely populated, covering an area of over , but home to roughly a quarter of Russia's population. Novosibirsk, Krasnoyarsk, and Omsk are the largest cities in the area. Because Siberia is a geographic and historic concept and not a political entity, there is no single precise definition of its territorial borders. Traditionally, Siberia spans the entire expanse of land from the Ural Mountains to the Pacific Ocean, with the Ural River usually forming the southernmost portion of its western boundary, and includes most of the drainage basin of the Arctic Ocean. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Baikal
Lake Baikal is a rift lake and the deepest lake in the world. It is situated in southern Siberia, Russia between the Federal subjects of Russia, federal subjects of Irkutsk Oblast, Irkutsk Oblasts of Russia, Oblast to the northwest and the Republic of Buryatia to the southeast. At —slightly larger than Belgium—Lake Baikal is the world's List of lakes by area, seventh-largest lake by surface area, as well as the second largest lake in Eurasia after the Caspian Sea. However, because it is also the List of lakes by depth, deepest lake, with a maximum depth of , Lake Baikal is the world's List of lakes by volume, largest freshwater lake by volume, containing of water or 22–23% of the world's fresh surface water, more than all of the North American Great Lakes combined. It is also the world's ancient lake, oldest lake at 25–30 million years, and among the clearest. It is estimated that the lake contains around 19% of the unfrozen fresh water on the planet. Lake Baikal ... [...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] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of Silicon dioxide, SiO2. Quartz is, therefore, classified structurally as a Silicate mineral#Tectosilicates, framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norway
Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of Norway. Bouvet Island, located in the Subantarctic, is a Dependencies of Norway, dependency, and not a part of the Kingdom; Norway also Territorial claims in Antarctica, claims the Antarctic territories of Peter I Island and Queen Maud Land. Norway has a population of 5.6 million. Its capital and largest city is Oslo. The country has a total area of . The country shares a long eastern border with Sweden, and is bordered by Finland and Russia to the northeast. Norway has an extensive coastline facing the Skagerrak strait, the North Atlantic Ocean, and the Barents Sea. The unified kingdom of Norway was established in 872 as a merger of Petty kingdoms of Norway, petty kingdoms and has existed continuously for years. From 1537 to 1814, Norway ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
