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Helgustaðir Mine
Helgustadir mine ( ) is a mine in the east of Iceland where Iceland spar (a form of transparent calcite) was mined from the mid-17th century to the 20th century. It is the source of the largest and clearest known Iceland spar specimen and the source of most museum specimens of Iceland spar. It was declared a nature reserve in 1975. About Location The mine is located near Eskifjörður, east of Iceland. Helgustadir mine consists of two mines, known as the upper and lower mine. Uses Crystals from this area are known for exceptional clarity, leading to the mineral being named "Iceland spar". Iceland spar from Helgustadir mine was used in optical devices used in physics, chemistry, and geology, most importantly Nicol prisms. Nature reserve The nature reserve is 0.9 hectares The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 10 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mining
Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic viability of investing in the equipment, labor, and energy required to extract, refine and transport the materials found at the mine to manufacturers who can use the material. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Region (Iceland)
Eastern Region ( is, Austurland ) is a region in eastern Iceland. Its area is and in 2020 its population was 13,173. The Eastern Regions has a jagged coastline of fjords, referred to as the Eastfjords ( ). The largest town in the region is Egilsstaðir, with a population of 2,300. The oldest municipality is Djúpivogur, which got their trading licence in 1589 and had a population of 470 in 2015. The only car and passenger ferry that sails between Iceland and the European continent calls at Seyðisfjörður once a week in the summer months and intermittently the rest of the year. The region is home to the Kárahnjúkar Hydropower Plant. Among notable tourist destinations are the Helgustaðir mine, which is known for its Iceland spar Iceland spar, formerly called Iceland crystal ( is, silfurberg , ) and also called optical calcite, is a transparent variety of calcite, or crystallized calcium carbonate, originally brought from Iceland, and used in demonstrating the polariza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iceland Spar
Iceland spar, formerly called Iceland crystal ( is, silfurberg , ) and also called optical calcite, is a transparent variety of calcite, or crystallized calcium carbonate, originally brought from Iceland, and used in demonstrating the polarization of light (see polarimetry). It occurs in large readily cleavable crystals, is easily divisible into parallelepipeds, and is remarkable for its birefringence. This means that the refractive index of the crystal is different for light of different polarization. A ray of unpolarized light passing through the crystal is divided into two rays of perpendicular polarization directed at different angles. This double refraction causes objects seen through the crystal to appear doubled. Historically, the double-refraction property of this crystal was important to understanding the nature of light as a wave. This was studied at length by Christiaan Huygens and Isaac Newton. Sir George Stokes also studied the phenomenon. Its complete explanation i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on Scratch hardness, scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses. Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite over timescales of days or less at temperatures exceeding 300 °C, and vaterite is even less stable. Etymology Calcite is derived from the German ''Calcit'', a term from the 19th century that came from the Latin word for Lime (material), lime, ''calx'' (genitive calcis) with the suffix "-ite" used to name minerals. It is thus etymologically related to chalk. When applied by archaeology, archaeologists and stone trade pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helgustaðanáma
Helgustadir mine ( ) is a mine in the east of Iceland where Iceland spar (a form of transparent calcite) was mined from the mid-17th century to the 20th century. It is the source of the largest and clearest known Iceland spar specimen and the source of most museum specimens of Iceland spar. It was declared a nature reserve in 1975. About Location The mine is located near Eskifjörður, east of Iceland. Helgustadir mine consists of two mines, known as the upper and lower mine. Uses Crystals from this area are known for exceptional clarity, leading to the mineral being named "Iceland spar". Iceland spar from Helgustadir mine was used in optical devices used in physics, chemistry, and geology, most importantly Nicol prisms. Nature reserve The nature reserve is 0.9 hectares The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 10 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eskifjörður
Eskifjörður (in original spelling; ), or Eskifjördur is a town and port in eastern Iceland with a large fishing industry. With a population of 1,043 it is one of the most populous towns in the municipality of Fjarðabyggð. History Eskifjörður had 302 inhabitants in 1901, 425 in 1910, 619 in 1920, 758 in 1930, 671 in 1940, 673 in 1950, 1741 in 1960, 936 in 1970 and 1 084 in 1981. It obtained the rights and privilegies of an official trading place (''verslunastaður'') as early as 1786 und was awarded municipal status (''kaupstðurréttindi'') on 10 April 1974. It developed into a booming community after Örum & Wulff, a powerful Danish trading company, had opened a trading post in 1798. In 1802 Kjartan Þórlaksson, the first Icelandic merchant who was not a Dane, settled down in Eskifjörður and started a successful business. Eskifjörður joined Neskaupstaður and Reyðarfjörður in 1998 to form the new municipality of Fjarðabyggð ("fjords-settlement"). Geography The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicol Prism
A Nicol prism is a type of polarizer, an optical device made from calcite crystal used to produce and analyse plane polarized light. It is made in such a way that it eliminates one of the rays by total internal reflection, i.e. the ordinary ray is eliminated and only the extraordinary ray is transmitted through the prism. It was the first type of polarizing prism, invented in 1828 by William Nicol (1770–1851) of Edinburgh. It consists of a rhombohedral crystal of Iceland spar (a variety of calcite) that has been cut at an angle of 68° with respect to the crystal axis, cut again diagonally, and then rejoined as shown, using a layer of transparent Canada balsam as a glue. Unpolarized light ray enters through the left face of the crystal, as shown in the diagram, and is split into two orthogonally polarized, differently directed rays by the birefringence property of calcite. The ''ordinary'' ray, or ''o''-ray, experiences a refractive index of ''n''o = 1.658 in the calcite and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcite Sample-Jenisch 91224-P4150799-black
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses. Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite over timescales of days or less at temperatures exceeding 300 °C, and vaterite is even less stable. Etymology Calcite is derived from the German ''Calcit'', a term from the 19th century that came from the Latin word for lime, ''calx'' (genitive calcis) with the suffix "-ite" used to name minerals. It is thus etymologically related to chalk. When applied by archaeologists and stone trade professionals, the term alabaster is used not just as in geology and mineralogy, where it is reserved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hectares
The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is about and one hectare contains about . In 1795, when the metric system was introduced, the ''are'' was defined as 100 square metres, or one square decametre, and the hectare ("hecto-" + "are") was thus 100 ''ares'' or km2 (10,000 square metres). When the metric system was further rationalised in 1960, resulting in the International System of Units (), the ''are'' was not included as a recognised unit. The hectare, however, remains as a non-SI unit accepted for use with the SI and whose use is "expected to continue indefinitely". Though the dekare/decare daa (1,000 m2) and are (100 m2) are not officially "accepted for use", they are still used in some contexts. Description The hectare (), although not a unit of SI, is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mindat
Mindat may refer to: Places in Burma/Myanmar *Mindat, Chin State, in Burma *Mindat Township, in Burma *Mindat District in Chin State, Burma Other uses *Mindat Min Kanaung Mintha ( my, ကနောင်မင်းသား; 31 January 1820 – 2 August 1866) was crown prince of Burma and son of King Tharrawaddy and younger brother of King Mindon of Burma. Towards the end of the Second Anglo-Burmese Wa ..., a Burmese prince * Mindat.org, an online mineralogy database {{dab, geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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