Anchor Stone Blocks ( German : Anker-Steinbaukasten ) are components of stone construction sets made in Rudolstadt , Germany , marketed as a construction toy .
123-457: Anchor Stone pieces are made of a mixture of quartz sand , chalk , and linseed oil (German Patent 13,770; US Patent 233,780), precisely pressed in molds so that they fit together perfectly. The stones come in three colors in imitation of the red brick , tan limestone , and blue slate of European buildings. They are not recommended for play by children under 3 years of age because of their small size (CE No. 0494). Anchor stones originated with
246-473: A druse (a layer of crystals lining a void), of which quartz geodes are particularly fine examples. The crystals are attached at one end to the enclosing rock, and only one termination pyramid is present. However, doubly terminated crystals do occur where they develop freely without attachment, for instance, within gypsum . α-quartz crystallizes in the trigonal crystal system, space group P 3 1 21 or P 3 2 21 (space group 152 or 154 resp.) depending on
369-672: A glass pyramid in the Louvre's central Cour Napoléon . The open spaces surrounding the pyramid were inaugurated on 15 October 1988, and its underground lobby was opened on 30 March 1989. New galleries of early modern French paintings on the 2nd floor of the Cour Carrée , for which the planning had started before the Grand Louvre , also opened in 1989. Further rooms in the same sequence, designed by Italo Rota , opened on 15 December 1992. On 18 November 1993, Mitterrand inaugurated
492-560: A pressure cooker . However, the quality and size of the crystals that were produced by these early efforts were poor. Elemental impurity incorporation strongly influences the ability to process and utilize quartz. Naturally occurring quartz crystals of extremely high purity, necessary for the crucibles and other equipment used for growing silicon wafers in the semiconductor industry, are expensive and rare. These high-purity quartz are defined as containing less than 50 ppm of impurity elements. A major mining location for high purity quartz
615-663: A burial context, such as Newgrange or Carrowmore in Ireland . Quartz was also used in Prehistoric Ireland , as well as many other countries, for stone tools ; both vein quartz and rock crystal were knapped as part of the lithic technology of the prehistoric peoples. While jade has been since earliest times the most prized semi-precious stone for carving in East Asia and Pre-Columbian America, in Europe and
738-601: A consequence, the works were removed after Louis-Philippe was deposed in 1848, and were eventually auctioned away in 1853. The short-lived Second Republic had more ambitions for the Louvre. It initiated repair work, the completion of the Galerie d'Apollon and of the salle des sept-cheminées , and the overhaul of the Salon Carré (former site of the iconic yearly Salon ) and of the Grande Galerie. In 1848,
861-472: A continuous framework of SiO 4 silicon–oxygen tetrahedra , with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO 2 . Quartz is, therefore, classified structurally as a 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,
984-487: A defining constituent of granite and other felsic igneous rocks . It is very common in sedimentary rocks such as sandstone and shale . It is a common constituent of schist , gneiss , quartzite and other metamorphic rocks . Quartz has the lowest potential for weathering in the Goldich dissolution series and consequently it is very common as a residual mineral in stream sediments and residual soils . Generally
1107-584: A high presence of quartz suggests a " mature " rock, since it indicates the rock has been heavily reworked and quartz was the primary mineral that endured heavy weathering. While the majority of quartz crystallizes from molten magma , quartz also chemically precipitates from hot hydrothermal veins as gangue , sometimes with ore minerals like gold, silver and copper. Large crystals of quartz are found in magmatic pegmatites . Well-formed crystals may reach several meters in length and weigh hundreds of kilograms. The largest documented single crystal of quartz
1230-526: A mixture of quartz sand, chalk, and linseed oil. Unfortunately, the Lilienthals, though brilliant inventors, had limited commercial success. The stone blocks saw little popularity until 1880, when Friedrich Adolf Richter , a wealthy businessman who had built a small empire in Rudolstadt, purchased the rights to the process for 1,000 marks , plus about 4800 marks (including 800 marks still owing) for
1353-573: A more focused museum of French, Western and Near Eastern art, covering a space ranging from Iran to the Atlantic. The collections of the Louvre's musée mexicain were transferred to the Musée d'Ethnographie du Trocadéro in 1887. As the Musée de Marine was increasingly constrained to display its core naval-themed collections in the limited space it had in the second-floor attic of the northern half of
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#17327873101911476-580: A new ceiling for the Salle des Bronzes (the former Salle La Caze ), a counterpoint to that of Braque installed in 1953 in the adjacent Salle Henri II . The room's floor and walls were redesigned in 2021 by Louvre architect Michel Goutal to revert the changes made by his predecessor Albert Ferran in the late 1930s, triggering protests from the Cy Twombly Foundation on grounds that the then-deceased painter's work had been created to fit with
1599-632: A new section of the museum complex located in a suite of lavishly decorated rooms on the first floor of the South Wing of the Cour Carrée. The Egyptian collection, initially curated by Jean-François Champollion , formed the basis for what is now the Louvre's Department of Egyptian Antiquities . It was formed from the purchased collections of Edmé-Antoine Durand , Henry Salt and the second collection of Bernardino Drovetti (the first one having been purchased by Victor Emmanuel I of Sardinia to form
1722-574: A small Brazilian mine, but it is also seen in Lower Silesia in Poland . Naturally occurring prasiolite is also found in the Thunder Bay area of Canada . Quartz crystals have piezoelectric properties; they develop an electric potential upon the application of mechanical stress . Quartz's piezoelectric properties were discovered by Jacques and Pierre Curie in 1880. Quartz is
1845-437: A submicroscopic distribution of colloidal ferric hydroxide impurities. Natural citrines are rare; most commercial citrines are heat-treated amethysts or smoky quartzes . However, a heat-treated amethyst will have small lines in the crystal, as opposed to a natural citrine's cloudy or smoky appearance. It is nearly impossible to differentiate between cut citrine and yellow topaz visually, but they differ in hardness . Brazil
1968-680: A superstition that it would bring prosperity. Citrine was first appreciated as a golden-yellow gemstone in Greece between 300 and 150 BC, during the Hellenistic Age . Yellow quartz was used prior to that to decorate jewelry and tools but it was not highly sought after. Milk quartz or milky quartz is the most common variety of crystalline quartz. The white color is caused by minute fluid inclusions of gas, liquid, or both, trapped during crystal formation, making it of little value for optical and quality gemstone applications. Rose quartz
2091-542: Is a form of quartz that ranges from a bright vivid violet to a dark or dull lavender shade. The world's largest deposits of amethysts can be found in Brazil, Mexico, Uruguay, Russia, France, Namibia, and Morocco. Sometimes amethyst and citrine are found growing in the same crystal. It is then referred to as ametrine . Amethyst derives its color from traces of iron in its structure. Blue quartz contains inclusions of fibrous magnesio-riebeckite or crocidolite . Inclusions of
2214-419: Is a monoclinic polymorph. Lechatelierite is an amorphous silica glass SiO 2 which is formed by lightning strikes in quartz sand . As quartz is a form of silica, it is a possible cause for concern in various workplaces. Cutting, grinding, chipping, sanding, drilling, and polishing natural and manufactured stone products can release hazardous levels of very small, crystalline silica dust particles into
2337-463: Is a primary identifier for the macrocrystalline varieties. Pure quartz, traditionally called rock crystal or clear quartz, is colorless and transparent or translucent and has often been used for hardstone carvings , such as the Lothair Crystal . Common colored varieties include citrine, rose quartz, amethyst, smoky quartz, milky quartz, and others. These color differentiations arise from
2460-400: Is a type of quartz that exhibits a pale pink to rose red hue. The color is usually considered as due to trace amounts of titanium , iron , or manganese in the material. Some rose quartz contains microscopic rutile needles that produce asterism in transmitted light. Recent X-ray diffraction studies suggest that the color is due to thin microscopic fibers of possibly dumortierite within
2583-523: Is often twinned , synthetic quartz is produced for use in industry. Large, flawless, single crystals are synthesized in an autoclave via the hydrothermal process . Like other crystals, quartz may be coated with metal vapors to give it an attractive sheen. Quartz is the most common material identified as the mystical substance maban in Australian Aboriginal mythology . It is found regularly in passage tomb cemeteries in Europe in
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#17327873101912706-513: Is permitted inside, but flash photography is forbidden. Beginning in 2012, Nintendo 3DS portable video game systems were used as the official museum audio guides. The following year, the museum contracted Nintendo to create a 3DS-based audiovisual visitor guide. Entitled Nintendo 3DS Guide: Louvre , it contains over 30 hours of audio and over 1,000 photographs of artwork and the museum itself, including 3D views, and also provides navigation thanks to differential GPS transmitters installed within
2829-729: Is the Spruce Pine Gem Mine in Spruce Pine, North Carolina , United States. Quartz may also be found in Caldoveiro Peak , in Asturias , Spain. By the 1930s, the electronics industry had become dependent on quartz crystals. The only source of suitable crystals was Brazil; however, World War II disrupted the supplies from Brazil, so nations attempted to synthesize quartz on a commercial scale. German mineralogist Richard Nacken (1884–1971) achieved some success during
2952-475: Is the leading producer of citrine, with much of its production coming from the state of Rio Grande do Sul . The name is derived from the Latin word citrina which means "yellow" and is also the origin of the word " citron ". Sometimes citrine and amethyst can be found together in the same crystal, which is then referred to as ametrine . Citrine has been referred to as the "merchant's stone" or "money stone", due to
3075-412: Is used for very accurate measurements of very small mass changes in the quartz crystal microbalance and in thin-film thickness monitors . Almost all the industrial demand for quartz crystal (used primarily in electronics) is met with synthetic quartz produced by the hydrothermal process. However, synthetic crystals are less prized for use as gemstones. The popularity of crystal healing has increased
3198-613: The Salle Henri II , next to the Salle La Caze . In the late 1960s, seats designed by Pierre Paulin were installed in the Grande Galerie . In 1972, the Salon Carré 's museography was remade with lighting from a hung tubular case, designed by Louvre architect Marc Saltet [ fr ] with assistance from designers André Monpoix [ fr ] , Joseph-André Motte and Paulin. In 1961,
3321-515: The Grande Galerie and Pavillon Denon was redecorated in 1886 by Edmond Guillaume [ fr ] , Lefuel's successor as architect of the Louvre, and opened as a spacious exhibition room. Edomond Guillaume also decorated the first-floor room at the northwest corner of the Cour Carrée , on the ceiling of which he placed in 1890 a monumental painting by Carolus-Duran , The Triumph of Marie de' Medici originally created in 1879 for
3444-497: The Pietà of Villeneuve-lès-Avignon . The expansion of the museum and its collections slowed after World War I, however, despite some prominent acquisitions such as Georges de La Tour 's Saint Thomas and Baron Edmond de Rothschild 's 1935 donation of 4,000 prints, 3,000 drawings, and 500 illustrated books. From the late 19th century, the Louvre gradually veered away from its mid-century ambition of universality to become
3567-729: The Al Waleed bin Talal Foundation and on a design by Mario Bellini and Rudy Ricciotti . In 2007, German painter Anselm Kiefer was invited to create a work for the North stairs of the Perrault Colonnade , Athanor . This decision announces the museum's reengagement with contemporary art under the direction of Henri Loyrette , fifty years after the institution's last order to a contemporary artists, George Braque . In 2010, American painter Cy Twombly completed
3690-579: The Austrian government for the keeping of works such as Veronese's Wedding at Cana which was exchanged for a large Le Brun or the repurchase of the Albani collection. For most of the 19th century, from Napoleon 's time to the Second Empire , the Louvre and other national museums were managed under the monarch's civil list and thus depended much on the ruler's personal involvement. Whereas
3813-665: The Austrian Monarchy . This treaty marked the completion of Napoleon's conquest of Italy and the end of the first phase of the French Revolutionary Wars . It compelled Italian cities to contribute pieces of art and heritage to Napoleon's "parades of spoils" through Paris before being put into the Louvre Museum. The Horses of Saint Mark , which had adorned the basilica of San Marco in Venice after
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3936-479: The Château de Valençay . On 27 August 1939, after two days of packing, truck convoys began to leave Paris. By 28 December, the museum was cleared of most works, except those that were too heavy and "unimportant paintings [that] were left in the basement". In early 1945, after the liberation of France, art began returning to the Louvre. New arrangements after the war revealed the further evolution of taste away from
4059-450: The Count of Provence (the future king, Louis XVIII) by the king in 1778. Under Louis XVI , the idea of a royal museum in the Louvre came closer to fruition. The comte d'Angiviller broadened the collection and in 1776 proposed to convert the Grande Galerie of the Louvre – which at that time contained the plans-reliefs or 3D models of key fortified sites in and around France – into
4182-600: The Cour Carrée 's northern wing opened after comprehensive refurbishment. In January 2020, under the direction of Jean-Luc Martinez , the museum inaugurated a new contemporary art commission, L'Onde du Midi by Venezuelan kinetic artist Elias Crespin . The sculpture hovers under the Escalier du Midi, the staircase on the South of the Perrault Colonnade . The Louvre, like many other museums and galleries, felt
4305-632: The French Navy created an exhibition of ship models in the Louvre in December 1827, initially named musée dauphin in honor of Dauphin Louis Antoine , building on an 18th-century initiative of Henri-Louis Duhamel du Monceau . This collection, renamed musée naval in 1833 and later to develop into the Musée national de la Marine , was initially located on the first floor of the Cour Carrée's North Wing, and in 1838 moved up one level to
4428-545: The Grand Louvre overhaul of the late 1980s and 1990s, the Louvre had several street-level entrances, most of which are now permanently closed. Since 1993, the museum's main entrance has been the underground space under the Louvre Pyramid , or Hall Napoléon , which can be accessed from the Pyramid itself, from the underground Carrousel du Louvre, or (for authorized visitors) from the passage Richelieu connecting to
4551-582: The Guimet Museum in 1945. Nevertheless, the Louvre's first gallery of Islamic art opened in 1893. In the late 1920s, Louvre Director Henri Verne devised a master plan for the rationalization of the museum's exhibitions, which was partly implemented in the following decade. In 1932–1934, Louvre architects Camille Lefèvre [ fr ] and Albert Ferran redesigned the Escalier Daru to its current appearance. The Cour du Sphinx in
4674-674: The Louvre and Deutsches Museum . They appear in a fairly prominent role in Jan Švankmajer 's fantasy film Neco z Alenky as, among other things, the home of the White Rabbit. They also support a plot sequence in The Diamond in the Window , by Jane Langton. Quartz sand Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide ). The atoms are linked in
4797-597: The Luxembourg Palace . Meanwhile, during the Third Republic (1870–1940) the Louvre acquired new artefacts mainly via donations, gifts, and sharing arrangements on excavations abroad. The 583-item Collection La Caze , donated in 1869 by Louis La Caze , included works by Chardin ; Fragonard , Rembrandt and Watteau . In 1883, the Winged Victory of Samothrace , which had been found in
4920-530: The Luxembourg Palace . A hall was opened by Le Normant de Tournehem and the Marquis de Marigny for public viewing of the "king's paintings" ( Tableaux du Roy ) on Wednesdays and Saturdays. The Luxembourg gallery included Andrea del Sarto 's Charity and works by Raphael ; Titian ; Veronese ; Rembrandt ; Poussin or Van Dyck . It closed in 1780 as a result of the royal gift of the Luxembourg palace to
5043-576: The Medieval Louvre fortress are visible in the basement of the museum. Due to urban expansion, the fortress eventually lost its defensive function, and in 1546 Francis I converted it into the primary residence of the French kings . The building was redesigned and extended many times to form the present Louvre Palace. In 1682, Louis XIV chose the Palace of Versailles for his household, leaving
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5166-570: The Napoleonic looting of art in Europe, Egypt and Syria , and the museum was renamed Musée Napoléon , but after Napoleon's abdication, many works seized by his armies were returned to their original owners. The collection was further increased during the reigns of Louis XVIII and Charles X , and during the Second French Empire the museum gained 20,000 pieces. Holdings have grown steadily through donations and bequests since
5289-477: The National Assembly decreed that the Louvre should be used as a museum to display the nation's masterpieces. The museum opened on 10 August 1793 with an exhibition of 537 paintings, the majority of the works being royal and confiscated church property. Because of structural problems with the building, the museum was closed from 1796 until 1801. The collection was increased under Napoleon , after
5412-464: The Third Republic . The collection is divided among eight curatorial departments: Egyptian Antiquities ; Near Eastern Antiquities ; Greek , Etruscan , and Roman Antiquities ; Islamic Art ; Sculpture; Decorative Arts ; Paintings; Prints and Drawings. The Musée du Louvre contains approximately 500,000 objects and displays 35,000 works of art in eight curatorial departments with more than 60,600 m (652,000 sq ft) dedicated to
5535-524: The hexagonal crystal system above 573 °C (846 K; 1,063 °F). The ideal crystal shape is a six-sided prism terminating with six-sided pyramid-like rhombohedrons at each end. In nature, quartz crystals are often twinned (with twin right-handed and left-handed quartz crystals), 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 typically form as
5658-514: The impact of the COVID-19 pandemic on the arts and cultural heritage . It was closed for six months during French coronavirus lockdowns and saw visitor numbers plunge to 2.7 million in 2020, from 9.6 million in 2019 and 10.2 million in 2018, which was a record year. In preparation for the 2024 Olympics , the Louvre staged an exhibit about the Games' history that links their ancient beginnings to
5781-566: The "French Museum". Many design proposals were offered for the Louvre's renovation into a museum, without a final decision being made on them. Hence the museum remained incomplete until the French Revolution. The Louvre finally became a public museum during the French Revolution. In May 1791, the National Constituent Assembly declared that the Louvre would be "a place for bringing together monuments of all
5904-694: The 10.1 million visitors it received in 2018. The Louvre is the most-visited museum in the world , ahead of the Vatican Museums . The Louvre museum is located inside the Louvre Palace , in the center of Paris, adjacent to the Tuileries Gardens . The two nearest Métro stations are Louvre-Rivoli and Palais Royal-Musée du Louvre , the latter having a direct underground access to the Carrousel du Louvre commercial mall. Before
6027-879: The 14th century in Middle High German and in East Central German and which came from the Polish dialect term twardy , which corresponds to the Czech term tvrdý ("hard"). Some sources, however, attribute the word's origin to the Saxon word Querkluftertz , meaning cross-vein ore . The Ancient Greeks referred to quartz as κρύσταλλος ( krustallos ) derived from the Ancient Greek κρύος ( kruos ) meaning "icy cold", because some philosophers (including Theophrastus ) understood
6150-529: The 14th century, Charles V converted the building from its military role into a residence. In 1546, Francis I started its rebuilding in French Renaissance style. After Louis XIV chose Versailles as his residence in 1682, construction works slowed to a halt. The royal move away from Paris resulted in the Louvre being used as a residence for artists, under Royal patronage. For example, four generations of craftsmen-artists from
6273-620: The 1930s and 1940s. After the war, many laboratories attempted to grow large quartz crystals. In the United States, the U.S. Army Signal Corps contracted with Bell Laboratories and with the Brush Development Company of Cleveland, Ohio to synthesize crystals following Nacken's lead. (Prior to World War II, Brush Development produced piezoelectric crystals for record players.) By 1948, Brush Development had grown crystals that were 1.5 inches (3.8 cm) in diameter,
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#17327873101916396-475: The 2nd-floor attic , where it remained for more than a century. Following the July Revolution , King Louis Philippe focused his interest on the repurposing of the Palace of Versailles into a Museum of French History conceived as a project of national reconciliation, and the Louvre was kept in comparative neglect. Louis-Philippe did, however, sponsor the creation of the musée assyrien to host
6519-578: The Aegean Sea in 1863, was prominently displayed as the focal point of the Escalier Daru . Major artifacts excavated at Susa in Iran, including the massive Apadana capital and glazed brick decoration from the Palace of Darius there, accrued to the Oriental (Near Eastern) Antiquities Department in the 1880s. The Société des amis du Louvre was established in 1897 and donated prominent works, such as
6642-544: The Boulle family were granted Royal patronage and resided in the Louvre. Meanwhile, the collections of the Louvre originated in the acquisitions of paintings and other artworks by the monarchs of the House of France . At the Palace of Fontainebleau , Francis collected art that would later be part of the Louvre's art collections, including Leonardo da Vinci 's Mona Lisa . The Cabinet du Roi consisted of seven rooms west of
6765-414: The Club of Anchor Friends, the state of Thuringia , and the European Union , Georg Plenge was able to resurrect the company as Anker Steinbaukasten GmbH. Production at the factory in Rudolstadt restarted 15 September 1994, and new sets were sold to Club members in October 1994. The new factory manufactures and sells all 15 of the sets in the main series (GK-NF) of Anchor sets as well as some sets modelling
6888-400: The Cour Carrée, many of its significant holdings of non-Western artefacts were transferred in 1905 to the Trocadéro ethnography museum, the National Antiquities Museum in Saint-Germain-en-Laye , and the Chinese Museum in the Palace of Fontainebleau . The Musée de Marine itself was relocated to the Palais de Chaillot in 1943. The Louvre's extensive collections of Asian art were moved to
7011-405: The Earth's crust exposed to high temperatures, thereby damaging materials containing quartz and degrading their physical and mechanical properties. Although many of the varietal names historically arose from the color of the mineral, current scientific naming schemes refer primarily to the microstructure of the mineral. Color is a secondary identifier for the cryptocrystalline minerals, although it
7134-412: The Finance Ministry accepted to leave the Pavillon de Flore at the southwestern end of the Louvre building, as Verne had recommended in his 1920s plan. New exhibition spaces of sculptures (ground floor) and paintings (first floor) opened there later in the 1960s, on a design by government architect Olivier Lahalle. In 1981, French President François Mitterrand proposed, as one of his Grands Projets ,
7257-409: The Galerie d'Apollon on the upper floor of the remodeled Petite Galerie. Many of the king's paintings were placed in these rooms in 1673, when it became an art gallery, accessible to certain art lovers as a kind of museum. In 1681, after the court moved to Versailles, 26 of the paintings were transferred there, somewhat diminishing the collection, but it is mentioned in Paris guide books from 1684 on, and
7380-452: The Grand Louvre plan to relocate the Finance Ministry , until then housed in the North Wing of the Louvre, and thus devote almost the entire Louvre building (except its northwestern tip, which houses the separate Musée des Arts Décoratifs ) to the museum which would be correspondingly restructured. In 1984 I. M. Pei , the architect personally selected by Mitterrand, proposed a master plan including an underground entrance space accessed through
7503-428: The Italians and their artistic and cultural sensibilities. After the French defeat at Waterloo , the looted works' former owners sought their return. The Louvre's administrator, Denon, was loath to comply in absence of a treaty of restitution. In response, foreign states sent emissaries to London to seek help, and many pieces were returned, though far from all. In 1815 Louis XVIII finally concluded agreements with
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#17327873101917626-420: The Louvre conducted an elaborate plan of evacuation of its art collection . When Germany occupied the Sudetenland , many important artworks such as the Mona Lisa were temporarily moved to the Château de Chambord . When war was formally declared a year later, most of the museum's paintings were sent there as well. Select sculptures such as Winged Victory of Samothrace and the Venus de Milo were sent to
7749-420: The Louvre primarily as a place to display the royal collection, including, from 1692, a collection of ancient Greek and Roman sculpture. In 1692, the building was occupied by the Académie des Inscriptions et Belles-Lettres and the Académie Royale de Peinture et de Sculpture , which in 1699 held the first of a series of salons. The Académie remained at the Louvre for 100 years. During the French Revolution ,
7872-423: The Louvre, upon a recommendation from his friend the art collector and dealer Jacques Kerchache [ fr ] . On his initiative, a selection of highlights from the collections of what would become the Musée du Quai Branly – Jacques Chirac was installed on the ground floor of the Pavillon des Sessions and opened in 2000, six years ahead of the Musée du Quai Branly itself. The main other initiative in
7995-476: The Michaelis Basilika in Hildesheim and the Brandenburg Gate . They are widely available in Germany, including in the KaDeWe department store in Berlin , and are readily available online. A new series of sets for younger children called Die neue Steinzeit ("the new Stone Age") was introduced in 2012. The sets tend to be expensive, but high-quality; antique sets are just as playable now as when they were originally produced. Sets being produced today are made to
8118-406: The Middle East the different varieties of quartz were the most commonly used for the various types of jewelry and hardstone carving , including engraved gems and cameo gems , rock crystal vases , and extravagant vessels. The tradition continued to produce objects that were very highly valued until the mid-19th century, when it largely fell from fashion except in jewelry. Cameo technique exploits
8241-404: The Naval Museum in the Cour Carrée's attic was brought under the common Louvre Museum management, a change which was again reversed in 1920. In 1850 under the leadership of curator Adrien de Longpérier , the musée mexicain opened within the Louvre as the first European museum dedicated to pre-Columbian art . The rule of Napoleon III was transformational for the Louvre, both the building and
8364-460: The South Wing was covered by a glass roof in 1934. Decorative arts exhibits were expanded in the first floor of the North Wing of the Cour Carrée , including some of France's first period room displays. In the late 1930s, The La Caze donation was moved to a remodeled Salle La Caze above the salle des Caryatides , with reduced height to create more rooms on the second floor and a sober interior design by Albert Ferran. During World War II ,
8487-568: The Vatican, had opened in November 1800 in Anne of Austria 's former summer apartment, located on the ground floor just below the Galerie d'Apollon. On 19 November 1802, Napoleon appointed Dominique Vivant Denon , a scholar and polymath who had participated in the Egyptian campaign of 1798–1801, as the museum's first director, in preference to alternative contenders such as antiquarian Ennio Quirino Visconti , painter Jacques-Louis David , sculptor Antonio Canova and architects Léon Dufourny or Pierre Fontaine . On Denon's suggestion in July 1803,
8610-469: The adjoining halls, in what is now the Richelieu Wing, were separately destroyed. But the museum was saved by the efforts of Paris firemen and museum employees led by curator Henry Barbet de Jouy . Following the end of the monarchy, several spaces in the Louvre's South Wing went to the museum. The Salle du Manège was transferred to the museum in 1879, and in 1928 became its main entrance lobby. The large Salle des Etats that had been created by Lefuel between
8733-431: The aftermath of the Grand Louvre project was Chirac's decision to create a new department of Islamic Art, by executive order of 1 August 2003, and to move the corresponding collections from their prior underground location in the Richelieu Wing to a more prominent site in the Denon Wing. That new section opened on 22 September 2012, together with collections from the Roman-era Eastern Mediterranean, with financial support from
8856-441: The air that workers breathe. Crystalline silica of respirable size is a recognized human carcinogen and may lead to other diseases of the lungs such as silicosis and pulmonary fibrosis . Not all varieties of quartz are naturally occurring. Some clear quartz crystals can be treated using heat or gamma-irradiation to induce color where it would not otherwise have occurred naturally. Susceptibility to such treatments depends on
8979-407: The bands of color in onyx and other varieties. Efforts to synthesize quartz began in the mid-nineteenth century as scientists attempted to create minerals under laboratory conditions that mimicked the conditions in which the minerals formed in nature: German geologist Karl Emil von Schafhäutl (1803–1890) was the first person to synthesize quartz when in 1845 he created microscopic quartz crystals in
9102-462: The building. Between 1852 and 1870, the museum added 20,000 new artefacts to its collections. The main change of that period was to the building itself. In the 1850s architects Louis Visconti and Hector Lefuel created massive new spaces around what is now called the Cour Napoléon , some of which (in the South Wing, now Aile Denon) went to the museum. In the 1860s, Lefuel also led
9225-444: The chirality. Above 573 °C (846 K; 1,063 °F), α-quartz in P 3 1 21 becomes the more symmetric hexagonal P 6 4 22 (space group 181), and α-quartz in P 3 2 21 goes to space group P 6 2 22 (no. 180). These space groups are truly chiral (they each belong to the 11 enantiomorphous pairs). Both α-quartz and β-quartz are examples of chiral crystal structures composed of achiral building blocks (SiO 4 tetrahedra in
9348-659: The collection, the Republic dedicated 100,000 livres per year. In 1794, France's revolutionary armies began bringing pieces from Northern Europe, augmented after the Treaty of Tolentino (1797) by works from the Vatican, such as the Laocoön and Apollo Belvedere , to establish the Louvre as a museum and as a "sign of popular sovereignty". The early days were hectic. Privileged artists continued to live in residence, and
9471-488: The collections. The Greek and Roman sculpture gallery on the ground floor of the southwestern side of the Cour Carrée was completed on designs by Percier and Fontaine . In 1819 an exhibition of manufactured products was opened in the first floor of the Cour Carrée's southern wing and would stay there until the mid-1820s. Charles X in 1826 created the Musée Égyptien and in 1827 included it in his broader Musée Charles X ,
9594-566: The core of the present Museo Egizio in Turin ). The Restoration period also saw the opening in 1824 of the Galerie d'Angoulême , a section of largely French sculptures on the ground floor of the Northwestern side of the Cour Carrée, many of whose artefacts came from the Palace of Versailles and from Alexandre Lenoir's Musée des Monuments Français following its closure in 1816. Meanwhile,
9717-529: The creation of the pavillon des Sessions with a new Salle des Etats closer to Napoleon III's residence in the Tuileries Palace , with the effect of shortening the Grande Galerie by about a third of its previous length. A smaller but significant Second Empire project was the decoration of the salle des Empereurs below the Salon carré . The Louvre narrowly escaped serious damage during
9840-466: The crystal structure. Prase is a green variety of quartz. The green color is caused by inclusions of amphibole . Prasiolite , also known as vermarine , is a variety of quartz that is green in color. The green is caused by iron ions. It is a rare mineral in nature and is typically found with amethyst; most "prasiolite" is not natural – it has been artificially produced by heating of amethyst. Since 1950 , almost all natural prasiolite has come from
9963-485: The crystals. Tridymite and cristobalite are high-temperature polymorphs of SiO 2 that occur in high-silica volcanic rocks. Coesite is a denser polymorph of SiO 2 found in some meteorite impact sites and in metamorphic rocks formed at pressures greater than those typical of the Earth's crust. Stishovite is a yet denser and higher-pressure polymorph of SiO 2 found in some meteorite impact sites. Moganite
10086-517: The demand for natural quartz crystals, which are now often mined in developing countries using primitive mining methods, sometimes involving child labor . Louvre The Louvre ( English: / ˈ l uː v ( r ə )/ LOOV( -rə) ), or the Louvre Museum (French: Musée du Louvre [myze dy luvʁ] ), is a national art museum in Paris , France, and one of
10209-650: The end of the first era for Anchor Stones. Although Anchor Stones survived World War I and World War II , the factory was included within Communist East Germany when the Iron Curtain divided Europe. In 1953, the company was nationalized as VEB Anker-Steinbaukasten, a state-owned company. In 1963, the production of the blocks was stopped. The trademark "Anker" was used by various toy companies in East Germany, none of which were related to
10332-407: The first six days of which were reserved for visits by artists and foreigners and the last three for visits by the general public. In the early 1800s, after the seven-day week had been reinstated, the general public had only four hours of museum access per weeks, between 2pm and 4pm on Saturdays and Sundays. In 1824, a new regulation allowed public access only on Sundays and holidays; the other days
10455-442: The hands. This idea persisted until at least the 17th century. He also knew of the ability of quartz to split light into a spectrum . In the 17th century, Nicolas Steno 's study of quartz paved the way for modern crystallography . He discovered that regardless of a quartz crystal's size or shape, its long prism faces always joined at a perfect 60° angle. Quartz belongs to the trigonal crystal system at room temperature, and to
10578-437: The impurities of phosphate and aluminium that formed crystalline rose quartz, unlike the iron and microscopic dumortierite fibers that formed rose quartz. Smoky quartz is a gray, translucent version of quartz. It ranges in clarity from almost complete transparency to a brownish-gray crystal that is almost opaque. Some can also be black. The translucency results from natural irradiation acting on minute traces of aluminum in
10701-452: The largest at that time. By the 1950s, hydrothermal synthesis techniques were producing synthetic quartz crystals on an industrial scale, and today virtually all the quartz crystal used in the modern electronics industry is synthetic. An early use of the piezoelectricity of quartz crystals was in phonograph pickups. One of the most common piezoelectric uses of quartz today is as a crystal oscillator . The quartz oscillator or resonator
10824-555: The late 12th century to protect the city from the attack from the West, as the Kingdom of England still held Normandy at the time. Remnants of the Medieval Louvre are still visible in the crypt. Whether this was the first building on that spot is not known, and it is possible that Philip modified an existing tower. The origins of the name "Louvre" are somewhat disputed. According to the authoritative Grand Larousse encyclopédique ,
10947-458: The lavish decorative practices of the late 19th century. In 1947, Edmond Guillaume's ceiling ornaments were removed from the Salle des Etats , where the Mona Lisa was first displayed in 1966. Around 1950, Louvre architect Jean-Jacques Haffner [ fr ] streamlined the interior decoration of the Grande Galerie . In 1953, a new ceiling by Georges Braque was inaugurated in
11070-517: The location from which the quartz was mined. Prasiolite, an olive colored material, is produced by heat treatment; natural prasiolite has also been observed in Lower Silesia in Poland. Although citrine occurs naturally, the majority is the result of heat-treating amethyst or smoky quartz. Carnelian has been heat-treated to deepen its color since prehistoric times. Because natural quartz
11193-421: The mineral dumortierite within quartz pieces often result in silky-appearing splotches with a blue hue. Shades of purple or gray sometimes also are present. "Dumortierite quartz" (sometimes called "blue quartz") will sometimes feature contrasting light and dark color zones across the material. "Blue quartz" is a minor gemstone. Citrine is a variety of quartz whose color ranges from pale yellow to brown due to
11316-571: The mineral to be a form of supercooled ice. Today, the term rock crystal is sometimes used as an alternative name for transparent coarsely crystalline quartz. Roman naturalist Pliny the Elder believed quartz to be water ice , permanently frozen after great lengths of time. He supported this idea by saying that quartz is found near glaciers in the Alps, but not on volcanic mountains, and that large quartz crystals were fashioned into spheres to cool
11439-454: The monarchy's demise, as Muséum central des Arts de la République . The public was given free accessibility on three days per week, which was "perceived as a major accomplishment and was generally appreciated". The collection showcased 537 paintings and 184 objects of art. Three-quarters were derived from the royal collections, the remainder from confiscated émigrés and Church property ( biens nationaux ). To expand and organize
11562-434: The monumental Assyrian sculpture works brought to Paris by Paul-Émile Botta , in the ground-floor gallery north of the eastern entrance of the Cour Carrée. The Assyrian Museum opened on 1 May 1847. Separately, Louis-Philippe had his Spanish gallery displayed in the Louvre from 7 January 1838, in five rooms on the first floor of the Cour Carrée's East ( Colonnade ) Wing, but the collection remained his personal property. As
11685-501: The most commonly used minerals in the making of jewelry and hardstone carvings , especially in Europe and Asia. Quartz is the mineral defining the value of 7 on the Mohs scale of hardness , a qualitative scratch method for determining the hardness of a material to abrasion. The word "quartz" is derived from the German word Quarz , which had the same form in the first half of
11808-578: The most famous museums in the world. It is located on the Right Bank of the Seine in the city's 1st arrondissement (district or ward) and home to some of the most canonical works of Western art , including the Mona Lisa , Venus de Milo , and Winged Victory . The museum is housed in the Louvre Palace , originally built in the late 12th to 13th century under Philip II . Remnants of
11931-545: The most iconic collection remained that of paintings in the Grande Galerie , a number of other initiatives mushroomed in the vast building, named as if they were separate museums even though they were generally managed under the same administrative umbrella. Correspondingly, the museum complex was often referred to in the plural (" les musées du Louvre ") rather than singular. During the Bourbon Restoration (1814–1830), Louis XVIII and Charles X added to
12054-416: The museum itself was renamed Musée Napoléon . The collection grew through successful military campaigns. Acquisitions were made of Spanish, Austrian, Dutch, and Italian works, either as the result of war looting or formalized by treaties such as the Treaty of Tolentino . At the end of Napoleon's First Italian Campaign in 1797, the Treaty of Campo Formio was signed with Count Philipp von Cobenzl of
12177-468: The museum was open only to artists and foreigners, except for closure on Mondays. That changed in 1855 when the museum became open to the public all days except Mondays. It was free until 1922, when an entrance fee was introduced except on Sundays. Since its post- World War II reopening in 1946, the Louvre has been closed on Tuesdays, and habitually open to the public the rest of the week except for some holidays. The use of cameras and video recorders
12300-423: The museum. The upgraded 2013 Louvre guide was also announced in a special Nintendo Direct featuring Satoru Iwata and Shigeru Miyamoto demonstrating it at the museum, and 3DS XLs pre-loaded with the guide are available to rent at the museum. As of August 2023, there are virtual tours through rooms and galleries accessible online. The Louvre Palace , which houses the museum, was begun by King Philip II in
12423-541: The museum. In 1852, he created the Musée des Souverains in the Colonnade Wing , an ideological project aimed at buttressing his personal legitimacy. In 1861, he bought 11,835 artworks including 641 paintings, Greek gold and other antiquities of the Campana collection . For its display, he created another new section within the Louvre named Musée Napoléon III , occupying a number of rooms in various parts of
12546-532: The name derives from an association with a wolf hunting den (via Latin: lupus , lower Empire: lupara ). In the 7th century, Burgundofara (also known as Saint Fare), abbess in Meaux, is said to have given part of her "Villa called Luvra situated in the region of Paris" to a monastery, even though it is doubtful that this land corresponded exactly to the present site of the Louvre. The Louvre Palace has been subject to numerous renovations since its construction. In
12669-596: The nearby rue de Rivoli . A secondary entrance at the Porte des Lions , near the western end of the Denon Wing, was created in 1999 but is not permanently open. The museum's entrance conditions have varied over time. Prior to the 1850s, artists and foreign visitors had privileged access. At the time of initial opening in 1793, the French Republican calendar had imposed ten-day "weeks" (French: décades ),
12792-728: The next major phase of the Grand Louvre plan: the renovated North (Richelieu) Wing in the former Finance Ministry site, the museum's largest single expansion in its entire history, designed by Pei, his French associate Michel Macary, and Jean-Michel Wilmotte . Further underground spaces known as the Carrousel du Louvre , centered on the Inverted Pyramid and designed by Pei and Macary, had opened in October 1993. Other refurbished galleries, of Italian sculptures and Egyptian antiquities, opened in 1994. The third and last main phase of
12915-512: 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 (846 K; 1,063 °F). 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 classified as gemstones . Since antiquity, varieties of quartz have been
13038-427: The permanent collection. The Louvre exhibits sculptures, objets d'art , paintings, drawings, and archaeological finds. At any given point in time, approximately 38,000 objects from prehistory to the 21st century are being exhibited over an area of 72,735 m (782,910 sq ft), making it the largest museum in the world . It received 8.9 million visitors in 2023, 14 percent more than in 2022, though below
13161-460: The plan unfolded mainly in 1997, with new renovated rooms in the Sully and Denon wings. A new entrance at the porte des Lions opened in 1998, leading on the first floor to new rooms of Spanish paintings. As of 2002, the Louvre's visitor count had doubled from its pre-Grand-Louvre levels. President Jacques Chirac , who had succeeded Mitterrand in 1995, insisted on the return of non-Western art to
13284-494: The presence of impurities which change the molecular orbitals, causing some electronic transitions to take place in the visible spectrum causing colors. The most important distinction between types of quartz is that of macrocrystalline (individual crystals visible to the unaided eye) and the microcrystalline or cryptocrystalline varieties ( aggregates of crystals visible only under high magnification). The cryptocrystalline varieties are either translucent or mostly opaque, while
13407-403: The present case). The transformation between α- and β-quartz only involves a comparatively minor rotation of the tetrahedra with respect to one another, without a change in the way they are linked. However, there is a significant change in volume during this transition, and this can result in significant microfracturing in ceramics during firing, in ornamental stone after a fire and in rocks of
13530-510: The quartz. Additionally, there is a rare type of pink quartz (also frequently called crystalline rose quartz) with color that is thought to be caused by trace amounts of phosphate or aluminium . The color in crystals is apparently photosensitive and subject to fading. The first crystals were found in a pegmatite found near Rumford , Maine , US, and in Minas Gerais , Brazil. The crystals found are more transparent and euhedral, due to
13653-517: The room's prior decoration. That same year, the Louvre commissioned French artist François Morellet to create a work for the Lefuel stairs, on the first floor. For L'esprit d'escalier Morellet redesigned the stairscase's windows, echoing their original structures but distorting them to create a disturbing optical effect. On 6 June 2014, the Decorative Arts section on the first floor of
13776-610: The sack of Constantinople in 1204, were brought to Paris where they were placed atop Napoleon's Arc de Triomphe du Carrousel in 1797. Under the Treaty of Tolentino, the two statues of the Nile and Tiber were taken to Paris from the Vatican in 1797, and were both kept in the Louvre until 1815. (The Nile was later returned to Rome, whereas the Tiber has remained in the Louvre to this day.) The despoilment of Italian churches and palaces outraged
13899-441: The same specifications as the antique ones, so they can be easily integrated. In addition to construction sets, the artificial stone formula has been used to produce simple flat puzzles, such as tangrams . Scientists, engineers, and designers like Max Born , J. Robert Oppenheimer , Albert Einstein , Ivan Sutherland and Walter Gropius developed their creativity by playing with Anchor blocks. Anchor blocks have been exhibited in
14022-490: The sciences and arts". On 10 August 1792, Louis XVI was imprisoned and the royal collection in the Louvre became national property. Because of fear of vandalism or theft, on 19 August, the National Assembly pronounced the museum's preparation urgent. In October, a committee to "preserve the national memory" began assembling the collection for display. The museum opened on 10 August 1793, the first anniversary of
14145-509: The stone building set factory. However, existing sets of old Anchor Stones remained very popular within the international community. In 1979, the Club van Ankervrienden ("Club of Anchor Friends") was founded in the Netherlands. Initially the membership was limited to Dutch members, but foreign members were admitted starting in 1983. Today the club has about 230 members. With the support of
14268-611: The suppression of the Paris Commune . On 23 May 1871, as the French Army advanced into Paris, a force of Communards led by Jules Bergeret [ fr ] set fire to the adjoining Tuileries Palace . The fire burned for forty-eight hours, entirely destroying the interior of the Tuileries and spreading to the north west wing of the museum next to it. The emperor's Louvre library ( Bibliothèque du Louvre ) and some of
14391-571: The tooling and machines being used to produce them. He developed a series of sets of individually-packaged stones, which quickly became popular. Promoted by extensive advertising, 42,000 sets were sold in 1883. In 1894, Richter applied his "Anchor" trademark to the Richter's Anchor Stone Building Sets ( Richters Anker-Steinbaukasten ). More than 600 different sets were produced over the multi-decade life of these sets; more than 1,000 stone shapes were made (CVA Stone Catalog). In 1910 Richter died, heralding
14514-414: The transparent varieties tend to be macrocrystalline. Chalcedony is a cryptocrystalline form of silica consisting of fine intergrowths of both quartz, and its monoclinic polymorph moganite . Other opaque gemstone varieties of quartz, or mixed rocks including quartz, often including contrasting bands or patterns of color, are agate , carnelian or sard, onyx , heliotrope , and jasper . Amethyst
14637-488: The unlabeled paintings hung "frame to frame from floor to ceiling". The structure itself closed in May 1796 due to structural deficiencies. It reopened on 14 July 1801, arranged chronologically and with new lighting and columns. On 15 August 1797, the Galerie d'Apollon was opened with an exhibition of drawings. Meanwhile, the Louvre's Gallery of Antiquity sculpture ( musée des Antiques ), with artefacts brought from Florence and
14760-493: The wooden building blocks designed by Friedrich Fröbel , the creator of the Kindergarten system of education. He had observed how children enjoyed playing with geometrically-shaped blocks. The first Anchor Stone was produced when Otto Lilienthal and his brother Gustav decided to make a model of a stone building, using miniature blocks of stone. To this end, they started production of a limited number of blocks, made of
14883-420: Was first developed by Walter Guyton Cady in 1921. George Washington Pierce designed and patented quartz crystal oscillators in 1923. The quartz clock is a familiar device using the mineral. Warren Marrison created the first quartz oscillator clock based on the work of Cady and Pierce in 1927. The resonant frequency of a quartz crystal oscillator is changed by mechanically loading it, and this principle
15006-541: Was found near Itapore , Goiaz , Brazil; it measured approximately 6.1 m × 1.5 m × 1.5 m (20 ft × 5 ft × 5 ft) and weighed over 39,900 kg (88,000 lb). Quartz is extracted from open pit mines . Miners occasionally use explosives to expose deep pockets of quartz. More frequently, bulldozers and backhoes are used to remove soil and clay and expose quartz veins, which are then worked using hand tools. Care must be taken to avoid sudden temperature changes that may damage
15129-464: Was shown to ambassadors from Siam in 1686. By the mid-18th century there were an increasing number of proposals to create a public gallery in the Louvre. Art critic Étienne La Font de Saint-Yenne in 1747 published a call for a display of the royal collection. On 14 October 1750, Louis XV decided on a display of 96 pieces from the royal collection, mounted in the Galerie royale de peinture of
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