Resarö is an island in the Stockholm archipelago and a locality in Vaxholm Municipality, Stockholm County, Sweden. It had 2,946 inhabitants in 2010. Resarö includes the hamlet of Ytterby, famous for the early research on rare earth metals conducted there; the old form of the name was Risarna. The first element is ris'brushwood' - the last element is derived from arin'gravel; the last element ö'island' was added in the 16th century
Feldspars are a group of rock-forming tectosilicate minerals that make up about 41% of the Earth's continental crust by weight. Feldspars crystallize from magma as veins in both intrusive and extrusive igneous rocks and are present in many types of metamorphic rock. Rock formed entirely of calcic plagioclase feldspar is known as anorthosite. Feldspars are found in many types of sedimentary rocks; the name feldspar derives from the German Feldspat, a compound of the words Feld, "field", Spat meaning "a rock that does not contain ore". The change from Spat to -spar was influenced by the English word spar, meaning a non-opaque mineral with good cleavage. Feldspathic refers to materials; the alternate spelling, has fallen out of use. This group of minerals consists of tectosilicates. Compositions of major elements in common feldspars can be expressed in terms of three endmembers: potassium feldspar endmember KAlSi3O8, albite endmember NaAlSi3O8, anorthite endmember CaAl2Si2O8. Solid solutions between K-feldspar and albite are called "alkali feldspar".
Solid solutions between albite and anorthite are called "plagioclase", or more properly "plagioclase feldspar". Only limited solid solution occurs between K-feldspar and anorthite, in the two other solid solutions, immiscibility occurs at temperatures common in the crust of the Earth. Albite is considered both alkali feldspar. Alkali feldspars are grouped into two types: those containing potassium in combination with sodium, aluminum, or silicon; the first of these include: orthoclase KAlSi3O8, sanidine AlSi3O8, microcline KAlSi3O8, anorthoclase AlSi3O8. Potassium and sodium feldspars are not miscible in the melt at low temperatures, therefore intermediate compositions of the alkali feldspars occur only in higher temperature environments. Sanidine is stable at the highest temperatures, microcline at the lowest. Perthite is a typical texture in alkali feldspar, due to exsolution of contrasting alkali feldspar compositions during cooling of an intermediate composition; the perthitic textures in the alkali feldspars of many granites can be seen with the naked eye.
Microperthitic textures in crystals are visible using a light microscope, whereas cryptoperthitic textures can be seen only with an electron microscope. Barium feldspars are considered alkali feldspars. Barium feldspars form as the result of the substitution of barium for potassium in the mineral structure; the barium feldspars are monoclinic and include the following: celsian BaAl2Si2O8, hyalophane 4O8. The plagioclase feldspars are triclinic; the plagioclase series follows: albite NaAlSi3O8, oligoclase AlSi2O8, andesine NaAlSi3O8—CaAl2Si2O8, labradorite AlSi2O8, bytownite AlSi2O8, anorthite CaAl2Si2O8. Intermediate compositions of plagioclase feldspar may exsolve to two feldspars of contrasting composition during cooling, but diffusion is much slower than in alkali feldspar, the resulting two-feldspar intergrowths are too fine-grained to be visible with optical microscopes; the immiscibility gaps in the plagioclase solid solutions are complex compared to the gap in the alkali feldspars. The play of colours visible in some feldspar of labradorite composition is due to fine-grained exsolution lamellae.
The specific gravity in the plagioclase series increases from albite to anorthite. Chemical weathering of feldspars results in the formation of clay minerals such as illite and kaolinite. About 20 million tonnes of feldspar were produced in 2010 by three countries: Italy and China. Feldspar is a common raw material used in glassmaking, to some extent as a filler and extender in paint and rubber. In glassmaking, alumina from feldspar improves product hardness and resistance to chemical corrosion. In ceramics, the alkalis in feldspar act as a flux. Fluxes melt at an early stage in the firing process, forming a glassy matrix that bonds the other components of the system together. In the US, about 66% of feldspar is consumed in glassmaking, including glass containers and glass fiber. Ceramics and other uses, such as fillers, accounted for the remainder. In earth sciences and archaeology, feldspars are used for K-Ar dating, argon-argon dating, luminescence dating. In October 2012, the Mars Curiosity rover analyzed a rock that turned out to have a high feldspar content.
List of minerals – A list of minerals for which there are articles on Wikipedia List of countries by feldspar production This article incorporates public domain material from the United States Geological Survey document: "Feldspar and nepheline syenite". Bonewitz, Ronald Louis. Rock and Gem. New York: DK Publishing. ISBN 978-0-7566-3342-4. Media related to Feldspar at Wikimedia Commons
The Stockholm archipelago is the largest archipelago in Sweden, the second-largest archipelago in the Baltic Sea. The water has a pH-value from 7.0 or lower, to be compared with 8.0 for seawater. Together with humic substances this sometimes causes a bit brownish water colour in the inner parts; the salinity varies between brackish water with poor salinity. In the outer parts of the archipelago, the salinity reaches around 0.6–0.7 per cent by weight, to be compared with at least 1.5 for beginning to taste salty and around 3.0 or more for proper oceanic water. Sea ice is formed in the inner parts every winter; the archipelago extends from Stockholm 60 kilometres to the east. In a north–south direction, it follows the coastline of the Södermanland and Uppland provinces, reaching from Öja island, south of Nynäshamn, to Väddö, north of Norrtälje, it is separated from Åland by a stretch of water named South Kvarken. A separate group of islands lies further north, near the town of Öregrund. Between Arholma and Landsort there are 24,000 islands and islets.
Some of the better-known islands are Dalarö, Finnhamn, Nässlingen, Husarö, Ingarö, Ljusterö, Möja, Nämdö, Rödlöga, Tynningö, Utö, Svartsö and Värmdö. The biggest towns of the archipelago, apart from Stockholm, are Nynäshamn and Norrtälje; the village of Ytterby, famous among chemists for naming no fewer than four chemical elements, is situated on Resarö in the Stockholm archipelago. The shipping routes from the Baltic to Stockholm pass through the archipelago. There are three main entrances suitable for deep-draught craft, those near Landsort, Söderarm; the Stockholm archipelago is a joint valley landscape, shaped – and is still being shaped – by post-glacial rebound. It was not until the Viking Age; the islands rise by about three millimeters each year. In 1719 the archipelago had an estimated population of 2,900, consisting of fishermen. Today the archipelago is a popular holiday destination with some 50,000 holiday cottages; the Stockholm Archipelago Foundation, dedicated to the preservation of the nature and culture of the archipelago, owns some 15% of its total area.
The inhabitants in the archipelago, from around the mid-1400s to the end of the second world war, were combined farmers and fishermen. Spring and autumn fishing was quite intensive in the outer archipelago from 1450 until the mid-1800s, many fishermen lived for long periods in the outer islands because of the long distances to their permanent houses in the inner archipelago; the combined farming and fishing culture lasted until around 1950–1955 when the younger generation, born during and directly after the war, started to leave the archipelago and look for jobs in the cities on the mainland. Today most of the small farms on the islands are closed and the fishing industry has disappeared. Many poets and artists have been influenced and fascinated by the Stockholm archipelago. Among them are August Strindberg, Ture Nerman, Roland Svensson, Ernst Didring and Aleister Crowley. Björn Ulvaeus and Benny Andersson from the group ABBA wrote most of their songs in a cabin located on the archipelago. Boating is an popular activity with the sailing race Ornö runt being the largest in the archipelago.
This annual race, organised by the Tyresö Boat Club, has taken place every year since 1973. It requires registration. There are different entry classes, with the family class being the least competitive. In the winter skaters make excursions over the ice. Visiting the larger islands in the archipelago is easy all year round, but during winter period the routes depend on the ice conditions. Several companies have regular routes; the largest ship owner company is Waxholmsbolaget owned by the Stockholm County government. Taxi boats are available. In summer the archipelago bristles with private boats filled with people who take advantage of Allemansrätt, a law which gives anyone the right to go ashore or anchor on any ground not in the direct vicinity of buildings. List of archipelagos Örsö Strömma Canal Stockholm archipelago 24,000 islands and islets. Nautical chart: International no. 1205, SE61, Baltic Sea, Sea of Åland. Jeppe Wikström, title Havsskärgård, 2004. Images from the outer parts of Stockholm archipelago.
ISBN 91-89204-80-8 The Archipelago Foundation
Gustavsberg is a Swedish porcelain company that originated in 1826. It broke up in the 1990s and was sold off in pieces, to the dismay of residents of the Gustavsberg area, but artisans continued producing ceramics and household porcelain in the Gustavsberg tradition. One of Gustavsberg's most famous collections is the "Nobel Porcelain" produced in 1994. One such artisan was Josef Ekberg, who as a young man, created many pieces for Gustavsberg; the Gustavsberg Porcelain Museum is an art and industrial history museum in Gustavsberg,which has its origins in objects preserved from the Gustavsberg Porcelain Factory production. The museum was not open for public viewing, but from 1956 there has been a museum open to the public, it is now run by Värmdö municipality. The municipality owns the property on the original factory site, while the object collection was donated to the National Museum by the previous owner to Gustavsbergs Factories, "Kooperativa Förbundet"; the basic exhibitions showing the history of porcelain from an international perspective, porcelain manufacture in Gustavsberg since the early 1800s, designs of Gustav's studio, in particular, Wilhelm Kåge, Stig Lindberg and Bernt Friberg and examples of functional porcelain from the 1900s.
The Museum Director is Kjell Lööw. Josef Ekberg ^ ^ Svensk uppslagsbok, Malmö 1932 ^ Tusenkonstnären Stig Lindberg, Gisela Eronn, kapitel "Serviser för folkhemmet", ISBN 91-518-4100-2 Minardi, Robin Hecht, "Scandinavian Art Pottery: Denmark and Sweden", Schiffer Publishing Ltd. Rev. 2nd Ed. 2005, p. 131-143, ISBN 0-7643-2239-7 Vintage ceramics website The Gustavsbergs Porcelain Museum website
Quartz is a mineral composed of silicon and oxygen atoms in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is the second most abundant mineral 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 573 °C. Since the transformation is accompanied by a significant change in volume, it can induce fracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz. Since antiquity, varieties of quartz have been the most used minerals in the making of jewelry and hardstone carvings in Eurasia; the word "quartz" is derived from the German word "Quarz", which had the same form in the first half of the 14th century in Middle High German in East Central German and which came from the Polish dialect term kwardy, which corresponds to the Czech term tvrdý.
The Ancient Greeks referred to quartz as κρύσταλλος derived from the Ancient Greek κρύος meaning "icy cold", because some philosophers believed the mineral to be a form of supercooled ice. Today, the term rock crystal is sometimes used as an alternative name for the purest form of quartz. Quartz belongs to the trigonal crystal system; the ideal crystal shape is a six-sided prism terminating with six-sided pyramids at each end. In nature quartz crystals are twinned, distorted, or so intergrown with adjacent crystals of quartz or other minerals as to only show part of this shape, or to lack obvious crystal faces altogether and appear massive. Well-formed crystals form in a'bed' that has unconstrained growth into a void. However, doubly terminated crystals do occur where they develop without attachment, for instance within gypsum. A quartz geode is such a situation where the void is spherical in shape, lined with a bed of crystals pointing inward. Α-quartz crystallizes in the trigonal crystal system, space group P3121 or P3221 depending on the chirality.
Β-quartz belongs to space group P6222 and P6422, respectively. These space groups are chiral. Both α-quartz and β-quartz are examples of chiral crystal structures composed of achiral building blocks; the transformation between α- and β-quartz only involves a comparatively minor rotation of the tetrahedra with respect to one another, without change in the way they are linked. Although many of the varietal names arose from the color of the mineral, current scientific naming schemes refer to the microstructure of the mineral. Color is a secondary identifier for the cryptocrystalline minerals, although it is a primary identifier for the macrocrystalline varieties. Pure quartz, traditionally called rock crystal or clear quartz, is colorless and transparent or translucent, has been used for hardstone carvings, such as the Lothair Crystal. Common colored varieties include citrine, rose quartz, smoky quartz, milky quartz, others; these color differentiation's arise from chromophores which have been incorporated into the crystal structure of the mineral.
Polymorphs of quartz include: α-quartz, β-quartz, moganite, cristobalite and stishovite. The most important distinction between types of quartz is that of macrocrystalline and the microcrystalline or cryptocrystalline varieties; the cryptocrystalline varieties are either translucent or opaque, while the transparent varieties tend to be macrocrystalline. Chalcedony is a cryptocrystalline form of silica consisting of fine intergrowths of both quartz, its monoclinic polymorph moganite. Other opaque gemstone varieties of quartz, or mixed rocks including quartz including contrasting bands or patterns of color, are agate, carnelian or sard, onyx and jasper. Amethyst is a form of quartz that ranges from a dull purple color; the world's largest deposits of amethysts can be found in Brazil, Uruguay, France and Morocco. Sometimes amethyst and citrine are found growing in the same crystal, it is referred to as ametrine. An amethyst is formed. Blue quartz contains inclusions of fibrous crocidolite. Inclusions of the mineral dumortierite within quartz pieces result in silky-appearing splotches with a blue hue, shades giving off purple and/or grey colors additionally being found.
"Dumortierite quartz" will sometimes feature contrasting light and dark color zones across the material. Interest in the certain quality forms of blue quartz as a collectible gemstone arises in India and in the United States. Citrine is a variety of quartz whose color ranges from a pale yellow to brown due to ferric impurities. Natural citrines are rare. However, a heat-treated amethyst will have small lines in the crystal, as opposed to a natural citrine's cloudy or smokey appearance, it is nearly impossible to differentiate between cut citrine and yellow topaz visually, but they differ in hardness. Brazil is the leading producer of citrine, with much
Geography of Stockholm
The City of Stockholm is situated on fourteen islands and on the banks to the archipelago where Lake Mälaren meets the Baltic Sea. The city centre is situated on the water; the area of Stockholm is one of several places in Sweden with a joint valley terrain. In these landscapes erosion along geological joints has split the flattish upper surfaces into low-lying plateaus. In the case of Stockholm the plateau surfaces are remnants of the Sub-Cambrian peneplain; the access to fresh water is excellent in Stockholm today, in contrast to the horrible state of things, when lakes and watercourses were used as refuse dumps and latrines, causing epidemic cholera and many other diseases. By the 1860s things changed, as water fetched from Årstaviken, the waters south of Södermalm, was treated in the first water-purifying plant at Skanstull and from there distributed through water mains. In modern times the city gets its water from Lake Mälaren purified by plants at Norsborg and Lovön, together producing 350,000 m³ per day, which means Stockholmers are consuming 200 litres per day on average.
Water is purified at three plants at Bromma and Loudden, together filtering some 400,000 m³ sewage per day from pollution, including nitrogen and phosphorus, before discharging it into the Baltic Sea. Levels of several pollutants in lakes in the central parts of the city on the western side, are far above average, including substances such as cadmium, copper and lead. Decreasing usage of several of these substances has reduced these levels in the upper sediments of the lakes; the Stockholm area used to contain a lot more lakes and watercourses than it does today, much due to post-glacial rebound, but because of lake reclaims for settlements and health. Historical lakes, such as Fatburssjön on Södermalm and Träsket on Norrmalm, were filthy and associated with the high mortality in Stockholm until the late 19th century. Other historical lakes, like Packartorgsviken and its interior part Katthavet, were filled with mud and stinky. Other lakes still present today were once much larger – such as Magelungen, Judarn, Råstasjön – while some bays of today once were proper lakes – Brunnsviken and Hammarby sjö.
Like in many other urban areas, the lakes of Stockholm are directly affected by the city's sewer system and pollution from settlements and industry. Sewers reduce the catchment areas of smaller lakes by redirecting surface water to Lake Mälaren or Lake Saltsjön. While nutritious substances such as phosphorus and nitrogen are derived from agriculture, urban areas produce high amounts of metals and organic compounds. In Stockholm, this applies to central bays – such as Klara sjö, Årstaviken, Ulvsundasjön, Riddarfjärden, Hammarby Sjö - but waters surrounded by bungalows and villas – like Långsjön in Älvsjö; the historical name for Stockholm Old Town was "The city between the bridges", a name, still used for the entire city which spans over numerous islands and hills. During the course of centuries, the city has seen many bridges relieve each other. In an urban code dated 1350, King Magnus IV prescribed the bridges leading over Norrström and Söderström to be built and maintained by the city of Stockholm together with six other cities surrounding Lake Mälaren, as they were the only land passage between the provinces Uppland and Södermanland and south of the city respectively.
In the view of the king, the city, a hundred years after its foundation, still couldn't afford to maintain its own bridges. Still, these first bridges were in no sense technically complicated or physically impressive, but rather simple wooden bridges, either floating bridges or beam bridges resting on poles or stone caissons, in either case with spans of no more than a few metres; the width corresponded to the directions for public roads, eight ell or 4,8 metres, more than enough for many centuries. The long and narrow bridges were demolished in case of siege, which besides the drawbridges necessary for the passing of ships, was an important defensive strategy; as the accounts of the city tells, spring floods and ice break-ups resulted in the frequent destruction of the bridges. By the mid 17th century, the population of the city had resulted in settlements north and south of Gamla stan, on Norrmalm and Södermalm, the number of bridges had grown if not their dimensions or quality. In a map dated 1640, three bridges connects Stadsholmen to Norrmalm passing over Helgeandsholmen, at the time still a group of islets.
Several new bridges of considerable length connected Norrmalm to the islets east of it. By the end of the 17th century, population growth resulted in an additional bridge north of Stadsholmen. One of the oldest bridges was located where today Stallbron is found south of the Riksdag Building; the first stone bridge, was built in front of the Royal Palace under Gustav III. Not until the 20th century, Stockholm was able to surpass the bays surrounding the city. Half of the about 30 bridges in central Stockholm were built most of them during the 1930s; this development was due to increasing traffic loads caused by a fivefold increase of vehicles in the 1920s. At Slussen, passing ships caused stationary rows of trams several hundreds metres long; the situatio
Yttrium is a chemical element with symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has been classified as a "rare-earth element". Yttrium is always found in combination with lanthanide elements in rare-earth minerals, is never found in nature as a free element. 89Y is the only stable isotope, the only isotope found in the Earth's crust. In 1787, Carl Axel Arrhenius found a new mineral near Ytterby in Sweden and named it ytterbite, after the village. Johan Gadolin discovered yttrium's oxide in Arrhenius' sample in 1789, Anders Gustaf Ekeberg named the new oxide yttria. Elemental yttrium was first isolated in 1828 by Friedrich Wöhler; the most important uses of yttrium are LEDs and phosphors the red phosphors in television set cathode ray tube displays. Yttrium is used in the production of electrodes, electronic filters, superconductors, various medical applications, tracing various materials to enhance their properties. Yttrium has no known biological role.
Exposure to yttrium compounds can cause lung disease in humans. Yttrium is a soft, silver-metallic and crystalline transition metal in group 3; as expected by periodic trends, it is less electronegative than its predecessor in the group and less electronegative than the next member of period 5, zirconium. Yttrium is the first d-block element in the fifth period; the pure element is stable in air in bulk form, due to passivation of a protective oxide film that forms on the surface. This film can reach a thickness of 10 µm; when finely divided, yttrium is unstable in air. Yttrium nitride is formed; the similarities of yttrium to the lanthanides are so strong that the element has been grouped with them as a rare-earth element, is always found in nature together with them in rare-earth minerals. Chemically, yttrium resembles those elements more than its neighbor in the periodic table, if physical properties were plotted against atomic number, it would have an apparent number of 64.5 to 67.5, placing it between the lanthanides gadolinium and erbium.
It also falls in the same range for reaction order, resembling terbium and dysprosium in its chemical reactivity. Yttrium is so close in size to the so-called'yttrium group' of heavy lanthanide ions that in solution, it behaves as if it were one of them. Though the lanthanides are one row farther down the periodic table than yttrium, the similarity in atomic radius may be attributed to the lanthanide contraction. One of the few notable differences between the chemistry of yttrium and that of the lanthanides is that yttrium is exclusively trivalent, whereas about half the lanthanides can have valences other than three; as a trivalent transition metal, yttrium forms various inorganic compounds in the oxidation state of +3, by giving up all three of its valence electrons. A good example is yttrium oxide known as yttria, a six-coordinate white solid. Yttrium forms a water-insoluble fluoride and oxalate, but its bromide, iodide and sulfate are all soluble in water; the Y3+ ion is colorless in solution because of the absence of electrons in the d and f electron shells.
Water reacts with yttrium and its compounds to form Y2O3. Concentrated nitric and hydrofluoric acids do not attack yttrium, but other strong acids do. With halogens, yttrium forms trihalides such as yttrium fluoride, yttrium chloride, yttrium bromide at temperatures above 200 °C. Carbon, selenium and sulfur all form binary compounds with yttrium at elevated temperatures. Organoyttrium chemistry is the study of compounds containing carbon–yttrium bonds. A few of these are known to have yttrium in the oxidation state 0; some trimerization reactions were generated with organoyttrium compounds as catalysts. These syntheses use YCl3 as a starting material, obtained from Y2O3 and concentrated hydrochloric acid and ammonium chloride. Hapticity is a term to describe the coordination of a group of contiguous atoms of a ligand bound to the central atom. Yttrium complexes were the first examples of complexes where carboranyl ligands were bound to a d0-metal center through a η7-hapticity. Vaporization of the graphite intercalation compounds graphite–Y or graphite–Y2O3 leads to the formation of endohedral fullerenes such as Y@C82.
Electron spin resonance studies indicated the formation of 3 − ion pairs. The carbides Y3C, Y2C, YC2 can be hydrolyzed to form hydrocarbons. Yttrium in the Solar System was created through stellar nucleosynthesis by the s-process, but by the r-process; the r-process consists of rapid neutron capture of lighter elements during supernova explosions. The s-process is a slow neutron capture of lighter elements inside pulsating red giant stars. Yttrium isotopes are among the most common products of the nuclear fission of uranium in nuclear explosions and nuclear reactors. In the context of nuclear waste management, the most important isotopes of yttrium