Micas ( / ˈ m aɪ k ə z / MY -kəz ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as perfect basal cleavage . Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in sedimentary rock . It is particularly prominent in many granites , pegmatites , and schists , and "books" (large individual crystals) of mica several feet across have been found in some pegmatites.
102-506: Shiprow is a historic street in the heart of Aberdeen , Scotland , near the harbour . Formerly the Shiprow sloped upward more gradually than it does now, and it crossed Union Street in a depression between St Catherine's Hill on the west and Castle Street, once high uneven ground, on the east. That the Shiprow has been made up several feet can be seen by a house at the end of Exchequer Row, and it crossed Union Street and entered Broad Street at
204-456: A commutator. The molding plate is also fabricated into tubes and rings for insulation in armatures, motor starters , and transformers. Segment plate acts as insulation between the copper commutator segments of direct-current universal motors and generators. Phlogopite built-up mica is preferred because it wears at the same rate as the copper segments. Although muscovite has a greater resistance to wear, it causes uneven ridges that may interfere with
306-560: A flaky or platy appearance. The crystal structure of mica is described as TOT-c , meaning that it is composed of parallel TOT layers weakly bonded to each other by cations ( c ). The TOT layers in turn consist of two tetrahedral sheets ( T ) strongly bonded to the two faces of a single octahedral sheet ( O ). The relatively weak ionic bonding between TOT layers gives mica its perfect basal cleavage. The tetrahedral sheets consist of silica tetrahedra, each silicon ion surrounded by four oxygen ions. In most micas, one in four silicon ions
408-503: A leading business hub and one of eight 'super cities' spearheading the UK's economy, marking it as the only city in Scotland so designated. In 2018, Aberdeen was found to be the best city in the UK to start a business in a study released by card payment firm Paymentsense. The Aberdeen area has seen human settlement for at least 8,000 years. The city began as two separate burghs : Old Aberdeen at
510-495: A lower level than the present. The Shiprow was one of the most important streets in the city, since it led from the harbour into the Castlegate area - the heart of Aberdeen. It is first mentioned in documents in 1281. Over the years it became more and more rundown and, although it had many historic connections, nearly all of it was demolished in the 1950s and 60s. Exchequer Row known locally as Cheq'ra Wynd (first mentioned in 1350)
612-660: A memorial to the consecration of the first bishop of the Episcopal Church in the United States of America , which took place nearby. In 1804, St Peter's Church , the first permanent Roman Catholic church in the city after the Reformation was built. Numerous other Protestant denominations have a presence in Aberdeen. The Salvation Army citadel on the Castlegate dominates the view of the east end of Union Street. In addition, there
714-401: A mica disc and contained in a borosilicate glass gas discharge tube (arc tube) and a metal cap. They include the sodium-vapor lamp that is the gas-discharge lamp in street lighting. Another use of mica is as a substrate in the production of ultra-flat, thin-film surfaces, e.g. gold surfaces. Although the deposited film surface is still rough due to deposition kinetics, the back side of
816-442: A mild abrasive to aid the polishing of the tooth surface and also adds a cosmetically pleasing, glittery shimmer to the paste. Mica is added to latex balloons to provide a colored shiny surface. Muscovite and phlogopite splittings can be fabricated into various built-up mica products, also known as micanite . Produced by mechanized or hand setting of overlapping splittings and alternate layers of binders and splittings, built-up mica
918-468: A mixture of 127 Incendiary, High Explosive and Cluster bombs were dropped on the city in one night. Two books written in 2018 and 2022 using bombing records held in London identified that unexploded bombs from the 1943 raid were found in the 1950s and 1980s making the bombs dropped 129 in total. Damage from the raid can still be seen in some parts of Aberdeen. The name given to Aberdeen translates as 'mouth of
1020-504: A new February high-temperature station record on 28 February 2012 of 17.2 °C (63.0 °F), and a new March high temperature record of 21.6 °C (70.9 °F) on 25 March 2012. The average temperature of the sea ranges from 6.6 °C (43.9 °F) in March to 13.8 °C (56.8 °F) in August. The Aberdeen locality population estimate is 198,590 (mid-2020 est.). For
1122-679: A new Town Hall was built and the first social services appeared with the Aberdeen Infirmary at Woolmanhill in 1739 and the Aberdeen Lunatic Asylum in 1800. The expensive infrastructure works led to the city becoming bankrupt in 1817 during the Post-Napoleonic depression , an economic downturn immediately after the Napoleonic Wars ; but the city's prosperity later recovered. The increasing economic importance of Aberdeen and
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#17328698622851224-535: A reflective color depending on the thickness of the coating. These products are used to produce automobile paint, shimmery plastic containers, and high-quality inks used in advertising and security applications. In the cosmetics industry, its reflective and refractive properties make mica an important ingredient in blushes , eye liner , eye shadow , foundation , hair and body glitter, lipstick , lip gloss , mascara , moisturizing lotions, and nail polish. Some brands of toothpaste include powdered white mica. This acts as
1326-724: A second deposit was located in the Xalla Complex, another palatial structure east of Street of the Dead. There is a claim mica was found within the Pyramid of the Sun, which originates from Peter Tompkins in his book Mysteries of the Mexican Pyramids . But it is not yet proven. Natural mica was and still is used by the Taos and Picuris Pueblos Indians in north-central New Mexico to make pottery. The pottery
1428-434: A strong negative charge since their bulk composition is AlSi 3 O 10 . The octahedral sheet has a positive charge, since its bulk composition is Al(OH) (for a dioctahedral sheet with the apical sites vacant) or M 3 (OH) 2 (for a trioctahedral site with the apical sites vacant; M represents a divalent ion such as ferrous iron or magnesium) The combined TOT layer has a residual negative charge, since its bulk composition
1530-439: Is birefringent and is therefore commonly used to make quarter and half wave plates . Specialized applications for sheet mica are found in aerospace components in air-, ground-, and sea-launched missile systems, laser devices, medical electronics and radar systems. Mica is mechanically stable in micrometer-thin sheets which are relatively transparent to radiation (such as alpha particles ) while being impervious to most gases. It
1632-403: Is 127 mi (204 km) northeast of Edinburgh and 536 mi (863 km) north of London . Aberdeen has a long, sandy coastline and features an oceanic climate , with cool summers and mild, rainy winters. During the mid-18th to mid-20th centuries, Aberdeen's buildings incorporated locally quarried grey granite , which may sparkle like silver because of its high mica content. Since
1734-487: Is Al 2 (AlSi 3 O 10 )(OH) 2 or M 3 (AlSi 3 O 10 )(OH) 2 . The remaining negative charge of the TOT layer is neutralized by the interlayer cations (typically sodium, potassium, or calcium ions). Because the hexagons in the T and O sheets are slightly different in size, the sheets are slightly distorted when they bond into a TOT layer. This breaks the hexagonal symmetry and reduces it to monoclinic symmetry. However,
1836-578: Is a Unitarian church, established in 1833 and located in Skene Terrace. Christadelphians have been present in Aberdeen since at least 1844. Over the years, they have rented space to meet at a number of locations and currently meet in the Inchgarth Community Centre in Garthdee. There is also a Quaker meetinghouse on Crown Street, the only purpose built Friends meeting house in Scotland that
1938-478: Is a stub . You can help Misplaced Pages by expanding it . Aberdeen Aberdeen ( / ˌ æ b ər ˈ d iː n / AB -ər- DEEN ; locally [ˌeːbərˈdin] or [ˈeːbərdin] ; Scottish Gaelic : Obar Dheathain [ˈopəɾ ˈʝɛ.ɪɲ] ) is a city in North East Scotland , and is the third most populous Scottish city . Historically, Aberdeen
2040-403: Is a higher percentage than both Glasgow and Edinburgh . In the household, there were 97,013 individual dwellings recorded in the city, of which 61% were privately owned, 9% privately rented and 23% rented from the council. The most popular type of dwellings are apartments which comprise 49% of residences followed by semi-detached at just below 22%. The median income of a household in the city
2142-531: Is also a Thai Buddhist temple located in the Hazelhead area of the city. There are no formal Hindu buildings, although there is a fortnightly Hindu religious gathering on the first and third Sunday afternoons at Queens Cross Parish church hall. The University of Aberdeen has a small Baháʼí society. Traditionally, Aberdeen was home to fishing, textile mills, shipbuilding and paper-making. These industries have been largely replaced. High technology developments in
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#17328698622852244-441: Is considerably less abundant than flake and scrap mica, and is occasionally recovered from mining scrap and flake mica. The most important sources of sheet mica are pegmatite deposits. Sheet mica prices vary with grade and can range from less than $ 1 per kilogram for low-quality mica to more than $ 2,000 per kilogram for the highest quality. In Madagascar and India, it is also mined artisanally , in poor working conditions and with
2346-552: Is derived from the Latin word mica , meaning a crumb , and probably influenced by micare , to glitter. Human use of mica dates back to prehistoric times. Mica was known to ancient Indian , Egyptian , Greek , Roman , and Chinese civilizations, as well as the Aztec civilization of the New World . The earliest use of mica has been found in cave paintings created during
2448-399: Is further north than almost all of Denmark and plenty of southern Sweden, being just south of Gothenburg in terms of latitude. Aberdeen features an oceanic climate ( Köppen Cfb ), with far milder winter temperatures than one might expect for its northern location. However, statistically speaking, it is still the coldest city in the UK. During the winter, especially throughout December,
2550-486: Is interest in the development of new energy sources, and technology transfer from oil into renewable energy and other industries is underway. The "Energetica" initiative led by Scottish Enterprise has been designed to accelerate this process. Aberdeen has become a major world centre for undersea petroleum technology. Mica Micas are used in products such as drywalls , paints , and fillers, especially in parts for automobiles, roofing, and in electronics. The mineral
2652-528: Is made from weathered Precambrian mica schist and has flecks of mica throughout the vessels. Tewa Pueblo Pottery is made by coating the clay with mica to provide a dense, glittery micaceous finish over the entire object. Mica flakes (called abrak in Urdu and written as ابرک ) are also used in Pakistan to embellish women's summer clothes, especially dupattas (long light-weight scarves, often colorful and matching
2754-400: Is replaced by an aluminium ion, while aluminium ions replace half the silicon ions in brittle micas. The tetrahedra share three of their four oxygen ions with neighbouring tetrahedra to produce a hexagonal sheet. The remaining oxygen ion (the apical oxygen ion) is available to bond with the octahedral sheet. The octahedral sheet can be dioctahedral or trioctahedral. A trioctahedral sheet has
2856-649: Is represented in the Parliament of the United Kingdom by two constituencies , Aberdeen North and Aberdeen South , which are wholly within the Aberdeen City council area. In the Scottish Parliament , the city is represented by three constituencies with different boundaries: Aberdeen Central and Aberdeen Donside are wholly within the Aberdeen City council area. Aberdeen South and North Kincardine includes
2958-477: Is resistant to corona discharge . Muscovite, the principal mica used by the electrical industry, is used in capacitors that are ideal for high frequency and radio frequency. Phlogopite mica remains stable at higher temperatures (to 900 °C (1,650 °F)) and is used in applications in which a combination of high-heat stability and electrical properties is required. Muscovite and phlogopite are used in sheet and ground forms. The leading use of dry-ground mica in
3060-447: Is stable when exposed to electricity, light, moisture, and extreme temperatures. It has superior electrical properties as an insulator and as a dielectric, and can support an electrostatic field while dissipating minimal energy in the form of heat; it can be split very thin (0.025 to 0.125 millimeters or thinner) while maintaining its electrical properties, has a high dielectric breakdown, is thermally stable to 500 °C (932 °F), and
3162-553: Is still in use today. In addition, there are a number of Baptist congregations in the city, and Evangelical congregations have been appearing in significant numbers since the late 2000s. The city also has two meeting houses of the Church of Jesus Christ of Latter-day Saints (LDS Church). There are also four mosques in Aberdeen which serve the Islamic community in the city. There is an Orthodox Jewish Synagogue established in 1945. There
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3264-451: Is therefore used as a window on radiation detectors such as Geiger–Müller tubes . In 2008, mica splittings represented the largest part of the sheet mica industry in the United States. Consumption of muscovite and phlogopite splittings was about 308 t in 2008. Muscovite splittings from India accounted for essentially all US consumption. The remainder was primarily imported from Madagascar. Small squared pieces of sheet mica are also used in
3366-414: Is unusual in that it is a good electrical insulator at the same time as being a good thermal conductor. The leading use of block mica is as an electrical insulator in electronic equipment. High-quality block mica is processed to line the gauge glasses of high-pressure steam boilers because of its flexibility, transparency, and resistance to heat and chemical attack. Only high-quality muscovite film mica, which
3468-468: Is used in cosmetics and food to add "shimmer" or "frost". The mica group comprises 37 phyllosilicate minerals . All crystallize in the monoclinic system, with a tendency towards pseudohexagonal crystals , and are similar in structure but vary in chemical composition. Micas are translucent to opaque with a distinct vitreous or pearly luster, and different mica minerals display colors ranging from white to green or red to black. Deposits of mica tend to have
3570-723: Is used in decorative coatings on wallpaper, concrete, stucco , and tile surfaces. It also is used as an ingredient in flux coatings on welding rods, in some special greases, and as coatings for core and mold release compounds, facing agents, and mold washes in foundry applications. Dry-ground phlogopite mica is used in automotive brake linings and clutch plates to reduce noise and vibration ( asbestos substitute); as sound-absorbing insulation for coatings and polymer systems; in reinforcing additives for polymers to increase strength and stiffness and to improve stability to heat, chemicals, and ultraviolet (UV) radiation; in heat shields and temperature insulation; in industrial coating additive to decrease
3672-450: Is used in electric motor and generator armatures, field coil insulation, and magnet and commutator core insulation. Mica consumption in flexible plates was about 21 tonnes in 2008 in the US. A heater plate is used where high-temperature insulation is required. The molding plate is sheet mica from which V-rings are cut and stamped for use in insulating the copper segments from the steel shaft ends of
3774-626: Is used primarily as an electrical insulation material. Mica insulation is used in high-temperature and fire-resistant power cables in aluminium plants, blast furnaces , critical wiring circuits (for example, defence systems, fire and security alarm systems, and surveillance systems), heaters and boilers, lumber kilns , metal smelters, and tanks and furnace wiring. Specific high-temperature mica-insulated wire and cable are rated to work for up to 15 minutes in molten aluminium, glass, and steel. Major products are bonding materials; flexible, heater, molding, and segment plates; mica paper; and tape. Flexible plate
3876-604: Is variously called India ruby mica or ruby muscovite mica, is used as a dielectric in capacitors . The highest quality mica film is used to manufacture capacitors for calibration standards . The next lower grade is used in transmitting capacitors . Receiving capacitors use a slightly lower grade of high-quality muscovite. Mica sheets are used to provide structure for heating wire (such as in Kanthal or Nichrome ) in heating elements and can withstand up to 900 °C (1,650 °F). Single-ended self-starting lamps are insulated with
3978-411: Is £16,813 (the mean income is £20,292) (2005) which places approximately 18% households in the city below the poverty line (defined as 60% of the mean income). Conversely, an Aberdeen postcode has the second highest number of millionaires of any postcode in the UK. The proportion of people residing in Aberdeen born outside the UK was 21.1% in 2022, compared with 15.9% in 2011 and 6.3% in 2001. Below are
4080-449: The Nara period . Yatsuomote ware is a type of local Japanese pottery from there. After an incident at Mount Yatsuomote a small bell was offered to soothe the kami . Katō Kumazō started a local tradition where small ceramic zodiac bells (きらら鈴) were made out of local mica kneaded into the clay , and after burning in the kiln the bell would make a pleasing sound when rung. Ayurveda ,
4182-612: The X ion is Ca, the mica is classed as a brittle mica. Brittle micas: Common micas: Brittle micas: Very fine-grained micas, which typically show more variation in ion and water content, are informally termed "clay micas". They include: Sericite is the name given to very fine, ragged grains and aggregates of white (colorless) micas. Mica is widely distributed and occurs in igneous , metamorphic and sedimentary regimes. Large crystals of mica used for various applications are typically mined from granitic pegmatites . The largest documented single crystal of mica ( phlogopite )
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4284-570: The oil industry and Aberdeen's seaport. Aberdeen Heliport is one of the busiest commercial heliports in the world, and the seaport is the largest in the north-east part of Scotland. A university town , the city is known for the University of Aberdeen , founded in 1495 as the fifth oldest university in the English-speaking world and located in Old Aberdeen . In 2012, HSBC named Aberdeen as
4386-715: The 14th century. Provost Ross's house , dating from 1593 and the second oldest house in the city, is located here. Since 1981, it has housed part of the Aberdeen Maritime Museum . Shiprow has changed dramatically in the last few years and now houses, alongside the Maritime Museum , the City Wharf office development, PureGym , Hotel Ibis, Lane7 Bowling Alley and Vue Cinema . 57°08′48″N 2°05′40″W / 57.14675°N 2.09457°W / 57.14675; -2.09457 This Aberdeen location article
4488-477: The 20th century. Catches have fallen because of overfishing and the use of the harbour by oil support vessels, and so although still an important fishing port it is now eclipsed by the more northerly ports of Peterhead and Fraserburgh . The Fisheries Research Services are headquartered in Aberdeen, and there is a marine research laboratory there. Aberdeen is well regarded for the agricultural and soil research carried out at The James Hutton Institute (formerly
4590-729: The East and West churches. At that time, the city also was home to houses of the Carmelites (Whitefriars) and Franciscans (Greyfriars). The latter survives in modified form as the chapel of Marischal College. St Machar's Cathedral was built twenty years after David I (1124–1153) transferred the pre-Reformation diocese from Mortlach in Banffshire to Old Aberdeen in 1137. Except the episcopate of William Elphinstone (1484–1511), building progressed slowly. Gavin Dunbar , who followed him in 1518, completed
4692-505: The English-held Aberdeen Castle before destroying it in 1308. It is still widely present in the city, throughout street names, business names and the city's Bon Accord shopping mall. The shield in the coat of arms is supported by two leopards . A local magazine is called the "Leopard" and, when Union Bridge was widened in the 20th century, small statues of the creature in a sitting position were cast and placed on top of
4794-508: The Hindu system of ancient medicine prevalent in India, includes the purification and processing of mica in preparing Abhraka bhasma, which is claimed as a treatment for diseases of the respiratory and digestive tracts. Mica dust in the workplace is regarded as a hazardous substance for respiratory exposure above certain concentrations. The Occupational Safety and Health Administration (OSHA) has set
4896-629: The Macaulay Land Use Research Institute), which has close links to the city's two universities. The Rowett Research Institute is a world-renowned research centre for studies into food and nutrition located in Aberdeen. It has produced three Nobel laureates and there is a high concentration of life scientists working in the city. As oil reserves in the North Sea decrease, there is an effort to rebrand Aberdeen as "Energy Capital of Europe" rather than "Oil Capital of Europe", and there
4998-637: The North Kincardine ward of Aberdeenshire Council . A further seven MSPs are elected as part of the North East Scotland electoral region. In the European Parliament the city was represented by six MEPs as part of the all-inclusive Scotland constituency. The arms and banner of the city show three silver towers on red. This motif dates from at least the time of Robert the Bruce and represents
5100-491: The US is in the joint compound for filling and finishing seams and blemishes in gypsum wallboard ( drywall ). The mica acts as a filler and extender, provides a smooth consistency, improves the workability of the compound, and provides resistance to cracking. In 2008, joint compounds accounted for 54% of dry-ground mica consumption. In the paint industry, ground mica is used as a pigment extender that also facilitates suspension, reduces chalking, prevents shrinking and shearing of
5202-445: The United States (53,000 t), South Korea (50,000 t), France (20,000 t) and Canada (15,000 t). The total global production was 350,000 t, although no reliable data were available for China. Most sheet mica was produced in India (3,500 t) and Russia (1,500 t). Flake mica comes from several sources: the metamorphic rock called schist as a byproduct of processing feldspar and kaolin resources, from placer deposits, and pegmatites. Sheet mica
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#17328698622855304-568: The Upper Paleolithic period (40,000 BC to 10,000 BC). The first hues were red ( iron oxide , hematite , or red ochre ) and black ( manganese dioxide , pyrolusite ), though black from juniper or pine carbons has also been discovered. White from kaolin or mica was used occasionally. A few kilometers northeast of Mexico City stands the ancient site of Teotihuacan . Mica was found in the noble palace complex "Viking Group" during an excavation led by Pedro Armillas between 1942 and 1944. Later,
5406-560: The adjoining Marischal College . The civic head and chair of the council is the Lord Provost . The council area is also divided into 30 community council areas , 29 of which had community councils operating as at August 2024. The first burgh of Aberdeen, covering just the New Aberdeen area near the mouth of the Dee, was created by David I (reigned 1124–1153). Neighbouring Old Aberdeen to
5508-544: The basis for the city's Common Good Fund which still benefits Aberdonians. During the Wars of Scottish Independence , Aberdeen was under English rule, so Robert the Bruce laid siege to Aberdeen Castle before destroying it in 1308, followed by executing the English garrison. The city was burned by Edward III of England in 1336, but was rebuilt and extended. The city was strongly fortified to prevent attacks by neighbouring lords, but
5610-419: The best surface properties of any filled plastic composite. In 2008, consumption of dry-ground mica in plastic applications accounted for 2% of the market. The rubber industry used ground mica as an inert filler and mold release compound in the manufacture of molded rubber products such as tires and roofing. The platy texture acts as an anti-blocking, anti-sticking agent. Rubber mold lubricant accounted for 1.5% of
5712-448: The buildings that stood on the three hills of medieval Aberdeen: Aberdeen Castle on Castle Hill (today's Castlegate ); the city gate on Port Hill; and a church on St Catherine's Hill (now levelled). "Bon Accord" is the motto of the city and is French for "Good Agreement". Legend tells that its use dates from a password used by Robert the Bruce during the 14th century Wars of Scottish Independence , when he and his men laid siege to
5814-589: The city spread beyond the (inferred) limits of the outlier onto the surrounding metamorphic/ igneous complexes formed during the Dalradian period (approximately 480–600 million years ago) with sporadic areas of igneous Diorite granites to be found, such as that at the Rubislaw quarry which was used to build much of the Victorian parts of the city. The city extends to 186 km (72 sq mi), and includes
5916-515: The city was plundered by both sides. In 1644, it was taken and ransacked by Royalist troops after the Battle of Aberdeen and two years later it was stormed by a Royalist force under the command of the George Gordon, 2nd Marquis of Huntly . An outbreak of bubonic plague over 1687 and 1688 killed 8.5% of the population, adding to the economic and demographic damage caused by war. In the 18th century,
6018-630: The city, with paper having been first made there in 1694. Paper-making has reduced in importance since the closures of Donside Paper Mill in 2001 and the Davidson Mill in 2005 leaving the Stoneywood Paper Mill with a workforce of approximately 500. Textile production ended in 2004 when Richards of Aberdeen closed. Grey granite was quarried at Rubislaw quarry for more than 300 years, and used for paving setts, kerb and building stones, and monumental and other ornamental pieces. Aberdeen granite
6120-537: The composition of the local council, and the affairs of the town. The Burgesses of the Guild were an integral part of the council for more than 700 years and played a considerable role in the growth and development of Aberdeen. In 1319, the Great Charter of Robert the Bruce transformed Aberdeen into a property-owning and financially independent community. Granted with it was the nearby Forest of Stocket, whose income formed
6222-459: The counties of Aberdeenshire and Kincardineshire . Aberdeen was made a county of itself in 1899. In 1975 the burgh was replaced by the larger City of Aberdeen district within the Grampian region. Further local government reforms in 1996 replaced the districts and regions created in 1975 with council areas; the pre-1996 City of Aberdeen district became the Aberdeen City council area. Aberdeen
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#17328698622856324-589: The development of the shipbuilding and fishing industries led to the construction of the present harbour including Victoria Dock and the South Breakwater, and the extension of the North Pier. Gas street lighting arrived in 1824 and an enhanced water supply appeared in 1830 when water was pumped from the Dee to a reservoir in Union Place. An underground sewer system replaced open sewers in 1865. The city absorbed
6426-519: The discovery of North Sea oil in 1969, Aberdeen has been known as the offshore oil capital of Europe. Based upon the discovery of prehistoric villages around the mouths of the rivers Dee and Don , the area around Aberdeen has been thought to have been settled for at least 6,000 years. Aberdeen received royal burgh status from David I of Scotland (1124–1153), which transformed the city economically. The traditional industries of fishing, paper-making, shipbuilding, and textiles have been overtaken by
6528-562: The dress). Thin mica flakes are added to a hot starch water solution, and the dupatta is dipped in this water mixture for 3–5 minutes. Then it is hung to air dry. Throughout the ages, fine powders of mica have been used for various purposes, including decorations. Powdered mica glitter is used to decorate traditional water clay pots in India, Pakistan and Bangladesh; it is also used on traditional Pueblo pottery, though not restricted to use on water pots in this case. The gulal and abir (colored powders) used by North Indian Hindus during
6630-435: The dry-ground mica used in 2008. As a rubber additive, mica reduces gas permeation and improves resiliency. Dry-ground mica is used in the production of rolled roofing and asphalt shingles , where it serves as a surface coating to prevent sticking of adjacent surfaces. The coating is not absorbed by freshly manufactured roofing because mica's platy structure is unaffected by the acid in asphalt or by weather conditions. Mica
6732-402: The electronics design and development industry, research in agriculture and fishing and the oil industry , which have been largely responsible for Aberdeen's economic growth, are now major parts of Aberdeen's economy. Until the 1970s, most of Aberdeen's leading industries dated from the 18th century; mainly these were textiles, foundry work, shipbuilding and paper-making, the oldest industry in
6834-439: The entire night. Temperatures at this time of year hover around 17.0 °C (62.6 °F) during the day in most of the urban area, though nearer 16.0 °C (60.8 °F) directly on the coast, and around 18.0 to 19.0 °C (64.4 to 66.2 °F) in the westernmost suburbs. Two weather stations collect climate data for the area, Aberdeen/Dyce Airport , and Craibstone. Both are about 4 + 1 ⁄ 2 miles (7 km) to
6936-491: The festive season of Holi contain fine crystals of mica to create a sparkling effect. The majestic Padmanabhapuram Palace , 65 km (40 mi) from Trivandrum in India, has colored mica windows. Mica powder is also used as a decoration in traditional Japanese woodblock printmaking , as when applied to wet ink with gelatin as thickener using kirazuri technique and allowed to dry, it sparkles and reflects light. Earlier examples are found among paper decorations, with
7038-633: The fifteen largest overseas-born groups in Aberdeen according to the 2022 census, alongside the two previous censuses. Christianity is the main religion practised in the city. Aberdeen's largest denominations are the Church of Scotland (through the Presbytery of Aberdeen ) and the Roman Catholic Church , both with numerous churches across the city, with the Scottish Episcopal Church having
7140-689: The film at the mica-film interface is ultra-flat once the film is removed from the substrate. Freshly-cleaved mica surfaces have been used as clean imaging substrates in atomic force microscopy , enabling for example the imaging of bismuth films, plasma glycoproteins , membrane bilayers , and DNA molecules. Thin transparent sheets of mica were used for peepholes in boilers, lanterns, stoves , and kerosene heaters because they were less likely to shatter than glass when exposed to extreme temperature gradients. Such peepholes were also fitted in horse-drawn carriages and early 20th-century cars, where they were called isinglass curtains . The word mica
7242-558: The first settlement of Aberdeen; this literally means "the mouth of the Don". The Celtic word aber means "river mouth", as in modern Welsh ( Aberystwyth , Aberdare , Aberbeeg etc.). The Scottish Gaelic name is Obar Dheathain (variation: Obairreadhain ; * obar presumably being a loan from the earlier Pictish; the Gaelic term is inbhir ), and in Latin , the Romans referred to
7344-452: The former burghs of Old Aberdeen, New Aberdeen, Woodside and the Torry area to the south of River Dee . In 2022, this gave the city a population density of 1,208 inhabitants per square kilometre (3,130/sq mi). The city is built on many hills, with the original beginnings of the city growing from Castle Hill, St. Catherine's Hill and Windmill Hill. When compared to mainland Europe, Aberdeen
7446-582: The gates were removed by 1770. Aberdeen's medieval council registers survive from 1398 onwards and are exceptional for their quantity and continuity among surviving Scottish burgh records. The earliest eight volumes, from 1398 to 1511, have been included in the UNESCO UK Memory of the World Register , and have been edited in a digital edition. During the Wars of the Three Kingdoms of 1644 to 1647
7548-476: The height as the Nishi Honganji 36 Poets Collection , codices of illuminated manuscripts in and after ACE 1112. For metallic glitter, Ukiyo-e prints employed very thick solution either with or without color pigments stencilled on hairpins, sword blades or fish scales on carp streamers ( 鯉のぼり , Koinobori ) . The soil around Nishio in central Japan is rich in mica deposits, which were already mined in
7650-539: The help of child labour . The commercially important micas are muscovite and phlogopite , which are used in a variety of applications. Mica's value is based on its unique physical properties: the crystalline structure of mica forms layers that can be split or delaminated into thin sheets usually causing foliation in rocks. These sheets are chemically inert, dielectric , elastic, flexible, hydrophilic, insulating, lightweight, platy, reflective, refractive, resilient, and range in opacity from transparent to opaque. Mica
7752-611: The legal limit ( permissible exposure limit ) for mica exposure in the workplace as 20 million parts per cubic foot (706,720,000 parts per cubic meter) over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 3 mg/m respiratory exposure over an 8-hour workday. At levels of 1,500 mg/m , mica is immediately dangerous to life and health . Some lightweight aggregates , such as diatomite , perlite , and vermiculite , may be substituted for ground mica when used as filler. Ground synthetic fluorophlogopite ,
7854-423: The length of the day is very short, averaging 6 hours and 41 minutes between sunrise and sunset at the winter solstice. As winter progresses, the length of the day grows fairly quickly, to 8 hours and 20 minutes by the end of January. Around summer solstice, the days will be around 18 hours long, having 17 hours and 55 minutes between sunrise and sunset. During this time of the year marginal nautical twilight lasts
7956-583: The loss of circulation by sealing porous sections of the drill hole. Well-drilling muds accounted for 15% of dry-ground mica use in 2008. The plastics industry used dry-ground mica as an extender and filler, especially in parts for automobiles as lightweight insulation to suppress sound and vibration. Mica is used in plastic automobiles fascia and fenders as a reinforcing material, providing improved mechanical properties and increased dimensional stability, stiffness, and strength. Mica-reinforced plastics also have high-heat dimensional stability, reduced warpage, and
8058-522: The mouth of the river Don ; and New Aberdeen, a fishing and trading settlement, where the Denburn waterway entered the river Dee estuary. The earliest charter was granted by William the Lion in 1179 and confirmed the corporate rights granted by David I . In 1214, Aberdeen Burgesses were granted a Royal Charter by Alexander II of Scotland giving them the sole right to form a Guild. This body exercised power in
8160-505: The national average of 19.2%. According to the 2011 census Aberdeen is 91.9% white, ethnically, 24.7% were born outside Scotland, higher than the national average of 16%. Of this population, 7.6% were born in other parts of the UK. 8.2% of Aberdonians stated to be from an ethnic minority (non-white) in the 2011 census, with 9,519 (4.3%) being Asian, with 3,385 (1.5%) coming from India and 2,187 (1.0%) being Chinese . The city has around 5,610 (2.6%) residents of African or Caribbean origin, which
8262-553: The neighbouring burghs of Old Aberdeen and Woodside plus the Torry area on the south bank of the Dee in 1891. Over the course of World War II Aberdeen was attacked 32 times by the German Luftwaffe . One of the most devastating attacks was on Wednesday 21 April 1943 when 29 Luftwaffe Dornier 217s flying from Stavanger , Norway attacked the city between the hours of 22:17 and 23:04. A total of 98 civilians and 27 servicemen were killed, along with 12,000 houses damaged, after
8364-456: The neighbouring burghs of Old Aberdeen and Woodside, plus the Torry area on the south bank of the Dee. The act of parliament which expanded the burgh also confirmed that Aberdeen was entitled to be called a city; it had commonly been described as a city prior to that, but (like most Scottish cities) without official recognition. Following the absorption of Torry in 1891, the city boundaries straddled
8466-486: The north was subsequently made a separate burgh in 1489. The burgh of Aberdeen was governed by a corporation, also known as the town council. As Aberdeen grew, the council's powers were inadequate to cater for the needs of the growing urban area. A separate police commission was established in 1795 with powers to levy taxes and provide infrastructure ('police' in this context being its older meaning of civic government rather than law enforcement). The first police commission
8568-426: The northwest of the city centre, and given that they are in close proximity to each other, exhibit very similar climatic regimes. Dyce tends to have marginally warmer daytime temperatures year-round owing to its slightly lower elevation, though it is more susceptible to harsh frosts. The coldest temperature to occur in recent years was −16.8 °C (1.8 °F) during December 2010, while the following winter, Dyce set
8670-532: The operation of a motor or generator. Consumption of segment plates was about 149 t in 2008 in the US. Some types of built-up mica have bonded splittings reinforced with cloth, glass, linen , muslin , plastic, silk, or special paper. These products are very flexible and are produced in wide, continuous sheets that are either shipped, rolled, or cut into ribbons or tapes, or trimmed to specified dimensions. Built-up mica products may also be corrugated or reinforced by multiple layering. In 2008, about 351 t of built-up mica
8772-401: The original hexahedral symmetry is discernible in the pseudohexagonal character of mica crystals. The short-range order of K ions on cleaved muscovite mica has been resolved. Chemically, micas can be given the general formula in which Structurally, micas can be classed as dioctahedral ( Y = 4) and trioctahedral ( Y = 6). If the X ion is K or Na, the mica is a common mica, whereas if
8874-468: The paint film, increases the resistance of the paint film to water penetration and weathering and brightens the tone of colored pigments. Mica also promotes paint adhesion in aqueous and oleoresinous formulations. Consumption of dry-ground mica in paint, the second-ranked use, accounted for 22% of the dry-ground mica used in 2008. Ground mica is used in the well-drilling industry as an additive to drilling fluids . The coarsely ground mica flakes help prevent
8976-451: The permeability of moisture and hydrocarbons; and in polar polymer formulations to increase the strength of epoxies, nylons, and polyesters . Wet-ground mica, which retains the brilliance of its cleavage faces, is used primarily in pearlescent paints by the automotive industry. Many metallic-looking pigments are composed of a substrate of mica coated with another mineral, usually titanium dioxide (TiO 2 ). The resultant pigment produces
9078-517: The railing posts (known locally as Kelly's Cats). The city's toast is "Happy to meet, sorry to part, happy to meet again". Being situated between two river mouths, the city has little natural exposure of bedrock. The small amount of geophysics done, and occasional building-related exposures, combined with small exposures in the banks of the River Don, suggest that it is actually sited on an inlier of Devonian "Old Red" sandstones and silts. The outskirts of
9180-518: The river Don', and is recorded as Aberdon in 1172 and Aberden in c. 1180 . The first element of the name is the Pictish word aber 'river mouth'. The second element is from the Celtic river goddess Devona . Aberdeen is usually described as within the historical Pictish territory and became Gaelic-speaking at some time in the medieval period. Old Aberdeen is the approximate location of Aberdon,
9282-446: The river as Devana . Medieval (or Ecclesiastical ) Latin has it as Aberdonia . The local Doric pronunciation, [ˌeːbərˈdin] or [ˈeːbərdin] (with a long ay sound), is frequently rendered Aiberdeen or Aiberdein . Aberdeen City is one of 32 council areas of Scotland , administered by Aberdeen City Council . The council meets at Aberdeen Town House and has its main offices in
9384-461: The structure by adding the two western spires and the southern transept. It is now a congregation of the Church of Scotland . Aberdeen has two other cathedrals: St. Mary's Cathedral is a Roman Catholic cathedral in Gothic style , erected in 1859. In addition, St. Andrew's Cathedral serves the Scottish Episcopal Church . It was constructed in 1817 as Archibald Simpson 's first commission and contains
9486-442: The structure of a sheet of the mineral brucite , with magnesium or ferrous iron being the most common cation. A dioctahedral sheet has the structure and (typically) the composition of a gibbsite sheet, with aluminium being the cation. Apical oxygens take the place of some of the hydroxyl ions that would be present in a brucite or gibbsite sheet, bonding the tetrahedral sheets tightly to the octahedral sheet. Tetrahedral sheets have
9588-574: The third-largest number. The census in 2022 showed that Aberdeen has the highest proportion of non-religious residents of any city in Scotland, with 58% of citizens claiming to have no religion. In the Middle Ages , the Kirk of St Nicholas was the only burgh kirk and one of Scotland's largest parish churches. Like a number of other Scottish kirks, it was subdivided after the Reformation , in this case into
9690-573: The traditional Japanese Kōdō ceremony to burn incense: A burning piece of coal is placed inside a cone made of white ash. The sheet of mica is placed on top, acting as a separator between the heat source and the incense, to spread the fragrance without burning it. Sheet mica is used principally in the electronic and electrical industries. Its usefulness in these applications is derived from its unique electrical and thermal properties and its mechanical properties, which allow it to be cut, punched, stamped, and machined to close tolerances. Specifically, mica
9792-425: The wider settlement of Aberdeen including Cove Bay and Dyce , the population estimate is 220,690 (mid-2020 est.). For Aberdeen City council area, the population estimate is 224,190 (2022). In 1396, the population was about 3,000. By 1801, it had become 26,992, then 153,503 in 1901, and finally 182,467 in 1941. The 2011 census showed fewer young people in Aberdeen, with 16.4% under 16, as opposed to
9894-573: Was a short congested lane connecting the Shiprow to the Castlegate, and on its right side, were a number of courts leading into an area crammed with insanitary dwellings which were later demolished. It was popularly supposed that the name Exchequer Row derived from the Aberdeen Mint which stood in the area. However, it comes from the name of the Royal Customs House - the Skakkarium, dating back to
9996-679: Was consumed in the US, mostly for molding plates (19%) and segment plates (42%). Sheet mica is a versatile and durable material widely used in electrical and thermal insulation applications. It exhibits excellent electrical properties, heat resistance, and chemical stability. Technical grade sheet mica is used in electrical components, electronics, atomic force microscopy and as window sheets. Other uses include diaphragms for oxygen-breathing equipment, marker dials for navigation compasses, optical filters , pyrometers , thermal regulators, stove and kerosene heater windows, radiation aperture covers for microwave ovens, and micathermic heater elements. Mica
10098-515: Was found in Lacey Mine, Ontario , Canada ; it measured 10 m × 4.3 m × 4.3 m (33 ft × 14 ft × 14 ft) and weighed about 330 tonnes (320 long tons; 360 short tons). Similar-sized crystals were also found in Karelia , Russia . Scrap and flake mica is produced all over the world. In 2010, the major producers were Russia (100,000 tonnes), Finland (68,000 t),
10200-429: Was short-lived, but it was resurrected in 1818 after the town council went bankrupt in 1817. From 1818 until 1871 there was a dual system of local government, with the town council and police commission having different roles in Aberdeen's administration. The police commission was eventually abolished in 1871 and its functions absorbed by the town council. In 1891 the city boundaries were significantly enlarged, absorbing
10302-456: Was used to build the terraces of the Houses of Parliament and Waterloo Bridge in London. Quarrying finally ceased in 1971. The current owners have begun pumping 40 years of rainwater from the quarry to develop a heritage centre on the site. In-shore fishing was once the predominant industry but was surpassed by deep-sea fisheries, which derived a great impetus from improved technologies throughout
10404-436: Was within the historic county of Aberdeenshire , but is now separate from the council area of Aberdeenshire . Aberdeen is one of Scotland's 32 local government council areas (as Aberdeen City ), and has a population of 198,590 (mid-2020 est.) for the urban area, making it the United Kingdom's 39th most populous built-up area , and 224,190 (2022) for the wider council area including outlying localities. The city
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