1.
Modernism
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Among the factors that shaped modernism were the development of modern industrial societies and the rapid growth of cities, followed then by reactions of horror to World War I. Modernism also rejected the certainty of Enlightenment thinking, and many modernists rejected religious belief, the poet Ezra Pounds 1934 injunction to Make it new. Was the touchstone of the approach towards what it saw as the now obsolete culture of the past. In this spirit, its innovations, like the novel, atonal and twelve-tone music, divisionist painting and abstract art. Modernism explicitly rejected the ideology of realism and makes use of the works of the past by the employment of reprise, incorporation, rewriting, recapitulation, revision, others focus on modernism as an aesthetic introspection. While J. M. W. Art critic Clement Greenberg describes the Pre-Raphaelite Brotherhood as proto-Modernists, There the proto-Modernists were, of all people, the Pre-Raphaelites actually foreshadowed Manet, with whom Modernist painting most definitely begins. They acted on a dissatisfaction with painting as practiced in their time, rationalism has also had opponents in the philosophers Søren Kierkegaard and later Friedrich Nietzsche, both of whom had significant influence on existentialism. A major 19th-century engineering achievement was The Crystal Palace, the huge cast-iron, Glass and iron were used in a similar monumental style in the construction of major railway terminals in London, such as Paddington Station and Kings Cross Station. These technological advances led to the building of structures like the Brooklyn Bridge. The latter broke all previous limitations on how tall man-made objects could be and these engineering marvels radically altered the 19th-century urban environment and the daily lives of people. Arguments arose that the values of the artist and those of society were not merely different, but that Society was antithetical to Progress, the philosopher Schopenhauer called into question the previous optimism, and his ideas had an important influence on later thinkers, including Nietzsche. Darwins theory of evolution by natural selection undermined religious certainty and the idea of human uniqueness, in particular, the notion that human beings were driven by the same impulses as lower animals proved to be difficult to reconcile with the idea of an ennobling spirituality. Karl Marx argued that there were fundamental contradictions within the capitalist system, historians, and writers in different disciplines, have suggested various dates as starting points for modernism. Everdell also thinks modernism in painting began in 1885–86 with Seurats Divisionism, the poet Baudelaires Les Fleurs du mal, and Flauberts novel Madame Bovary were both published in 1857. In the arts and letters, two important approaches developed separately in France, the first was Impressionism, a school of painting that initially focused on work done, not in studios, but outdoors. Impressionist paintings demonstrated that human beings do not see objects, the school gathered adherents despite internal divisions among its leading practitioners, and became increasingly influential. A significant event of 1863 was the Salon des Refusés, created by Emperor Napoleon III to display all of the paintings rejected by the Paris Salon. While most were in standard styles, but by artists, the work of Manet attracted tremendous attention
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Minimalism
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In visual arts, music, and other mediums, minimalism is a style that uses pared-down design elements. Minimalism began in post–World War II Western art, most strongly with American visual arts in the 1960s, prominent artists associated with minimalism include Donald Judd, John McCracken, Agnes Martin, Dan Flavin, Robert Morris, Anne Truitt, and Frank Stella. It derives from the reductive aspects of modernism and is interpreted as a reaction against abstract expressionism. Minimalism in music often features repetition and iteration such as those of the compositions of La Monte Young, Terry Riley, Steve Reich, Philip Glass, the term minimalist often colloquially refers to anything that is spare or stripped to its essentials. It has accordingly been used to describe the plays and novels of Samuel Beckett, the films of Robert Bresson, the stories of Raymond Carver, and the automobile designs of Colin Chapman. The word was first used in English in the early 20th century to describe a 1913 composition by the Russian painter Kasimir Malevich of a square on a white ground. Guggenheim Museum curated by Lawrence Alloway also in 1966 that showcased Geometric abstraction in the American art world via Shaped canvas, Color Field, in the wake of those exhibitions and a few others the art movement called minimal art emerged. Minimal art is inspired in part by the paintings of Barnett Newman, Ad Reinhardt, Josef Albers, and the works of artists as diverse as Pablo Picasso, Marcel Duchamp, Giorgio Morandi. Minimalism was also a reaction against the painterly subjectivity of Abstract Expressionism that had been dominant in the New York School during the 1940s and 1950s. The philosopher or art historian who can envision me—or anyone at all—arriving at aesthetic judgments in this way reads shockingly more into himself or herself than into my article. They very explicitly stated that their art was not about self-expression, in general, minimalisms features included geometric, often cubic forms purged of much metaphor, equality of parts, repetition, neutral surfaces, and industrial materials. Robert Morris, a theorist and artist, wrote a three part essay, Notes on Sculpture 1-3, originally published across three issues of Artforum in 1966. In these essays, Morris attempted to define a conceptual framework and formal elements for himself and these essays paid great attention to the idea of the gestalt - parts. Bound together in such a way that create a maximum resistance to perceptual separation. Morris later described an art represented by a marked lateral spread, the general shift in theory of which this essay is an expression suggests the transition into what would later be referred to as postminimalism. Stellas decisions about structures on the front surface of the canvas were therefore not entirely subjective, in the show catalog, Carl Andre noted, Art excludes the unnecessary. Frank Stella has found it necessary to paint stripes, there is nothing else in his painting. Because of a tendency in art to exclude the pictorial, illusionistic and fictive in favor of the literal, there was a movement away from painterly
3.
Barcelona
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Founded as a Roman city, in the Middle Ages Barcelona became the capital of the County of Barcelona. Barcelona has a cultural heritage and is today an important cultural centre. Particularly renowned are the works of Antoni Gaudí and Lluís Domènech i Montaner. The headquarters of the Union for the Mediterranean is located in Barcelona, the city is known for hosting the 1992 Summer Olympics as well as world-class conferences and expositions and also many international sport tournaments. It is a cultural and economic centre in southwestern Europe, 24th in the world. In 2008 it was the fourth most economically powerful city by GDP in the European Union, in 2012 Barcelona had a GDP of $170 billion, it is leading Spain in both employment rate and GDP per capita change. In 2009 the city was ranked Europes third and one of the worlds most successful as a city brand, since 2011 Barcelona has been a leading smart city in Europe. During the Middle Ages, the city was known as Barchinona, Barçalona, Barchelonaa. Internationally, Barcelonas name is abbreviated to Barça. However, this refers only to FC Barcelona, the football club. The common abbreviated form used by locals is Barna, another common abbreviation is BCN, which is also the IATA airport code of the Barcelona-El Prat Airport. The city is referred to as the Ciutat Comtal in Catalan. The origin of the earliest settlement at the site of present-day Barcelona is unclear, the ruins of an early settlement have been excavated in the El Raval neighbourhood, including different tombs and dwellings dating to earlier than 5000 BC. The founding of Barcelona is the subject of two different legends, the first attributes the founding of the city to the mythological Hercules. In about 15 BC, the Romans redrew the town as a castrum centred on the Mons Taber, under the Romans, it was a colony with the surname of Faventia, or, in full, Colonia Faventia Julia Augusta Pia Barcino or Colonia Julia Augusta Faventia Paterna Barcino. It enjoyed immunity from imperial burdens, the city minted its own coins, some from the era of Galba survive. Some remaining fragments of the Roman walls have incorporated into the cathedral. The cathedral, also known as the Basilica La Seu, is said to have founded in 343
4.
Catalonia
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Catalonia is an autonomous community of Spain, located on the northeastern extremity of the Iberian Peninsula. It is designated as a nationality by its Statute of Autonomy, Catalonia consists of four provinces, Barcelona, Girona, Lleida, and Tarragona. The capital and largest city is Barcelona, the second-most populated municipality in Spain, Catalonia comprises most of the territory of the former Principality of Catalonia. It is bordered by France and Andorra to the north, the Mediterranean Sea to the east, the official languages are Catalan, Spanish, and the Aranese dialect of Occitan. The eastern counties of these marches were united under the rule of the Frankish vassal the Count of Barcelona, in the later Middle Ages Catalan literature flourished. Between 1469 and 1516, the King of Aragon and the Queen of Castile married and ruled their kingdoms together, retaining all their distinct institutions, Courts, and constitutions. During the Franco-Spanish War, Catalonia revolted against a large and burdensome presence of the Royal army in its territory, within a brief period France took full control of Catalonia, at a high economic cost for Catalonia, until it was largely reconquered by the Spanish army. In the nineteenth century, Catalonia was severely affected by the Napoleonic, in the second half of the century Catalonia experienced industrialisation. As wealth from the industrial expansion grew, Catalonia saw a cultural renaissance coupled with incipient nationalism while several workers movements appeared. In 1914, the four Catalan provinces formed a Commonwealth, and with the return of democracy during the Second Spanish Republic, after the Spanish Civil War, the Francoist dictatorship enacted repressive measures, abolishing Catalan institutions and banning the official use of the Catalan language again. Since the Spanish transition to democracy, Catalonia has regained some political and cultural autonomy and is now one of the most economically dynamic communities of Spain, the origin of the name Catalunya is subject to diverse interpretations because of a lack of evidence. During the Middle Ages, Byzantine chroniclers claimed that Catalania derives from the medley of Goths with Alans. Other less plausible theories suggest, Catalunya derives from the land of castles, having evolved from the term castlà or castlan. This theory therefore suggests that the names Catalunya and Castile have a common root, the source is of Celtic origin, meaning chiefs of battle. Although the area is not known to have been occupied by Celts, the Lacetani, an Iberian tribe that lived in the area and whose name, due to the Roman influence, could have evolved by metathesis to Katelans and then Catalans. In English, Catalonia is pronounced /kætəˈloʊniə/, the native name, Catalunya, is pronounced in Central Catalan, the most widely spoken variety whose pronunciation is considered standard. The Spanish name is Cataluña, and the Aranese name is Catalonha, the first known human settlements in what is now Catalonia were at the beginning of the Middle Palaeolithic. From the next era, the Epipaleolithic or Mesolithic, important remains survive
5.
Spain
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By population, Spain is the sixth largest in Europe and the fifth in the European Union. Spains capital and largest city is Madrid, other urban areas include Barcelona, Valencia, Seville, Bilbao. Modern humans first arrived in the Iberian Peninsula around 35,000 years ago, in the Middle Ages, the area was conquered by Germanic tribes and later by the Moors. Spain is a democracy organised in the form of a government under a constitutional monarchy. It is a power and a major developed country with the worlds fourteenth largest economy by nominal GDP. Jesús Luis Cunchillos argues that the root of the span is the Phoenician word spy. Therefore, i-spn-ya would mean the land where metals are forged, two 15th-century Spanish Jewish scholars, Don Isaac Abravanel and Solomon ibn Verga, gave an explanation now considered folkloric. Both men wrote in two different published works that the first Jews to reach Spain were brought by ship by Phiros who was confederate with the king of Babylon when he laid siege to Jerusalem. This man was a Grecian by birth, but who had given a kingdom in Spain. He became related by marriage to Espan, the nephew of king Heracles, Heracles later renounced his throne in preference for his native Greece, leaving his kingdom to his nephew, Espan, from whom the country of España took its name. Based upon their testimonies, this eponym would have already been in use in Spain by c.350 BCE, Iberia enters written records as a land populated largely by the Iberians, Basques and Celts. Early on its coastal areas were settled by Phoenicians who founded Western Europe´s most ancient cities Cadiz, Phoenician influence expanded as much of the Peninsula was eventually incorporated into the Carthaginian Empire, becoming a major theater of the Punic Wars against the expanding Roman Empire. After an arduous conquest, the peninsula came fully under Roman Rule, during the early Middle Ages it came under Germanic rule but later, much of it was conquered by Moorish invaders from North Africa. In a process took centuries, the small Christian kingdoms in the north gradually regained control of the peninsula. The last Moorish kingdom fell in the same year Columbus reached the Americas, a global empire began which saw Spain become the strongest kingdom in Europe, the leading world power for a century and a half, and the largest overseas empire for three centuries. Continued wars and other problems led to a diminished status. The Napoleonic invasions of Spain led to chaos, triggering independence movements that tore apart most of the empire, eventually democracy was peacefully restored in the form of a parliamentary constitutional monarchy. Spain joined the European Union, experiencing a renaissance and steady economic growth
6.
Ludwig Mies van der Rohe
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Ludwig Mies van der Rohe was a German-American architect. He is commonly referred to and was addressed as Mies, his surname, along with Le Corbusier, Walter Gropius and Frank Lloyd Wright, he is widely regarded as one of the pioneers of modernist architecture. Mies, like many of his post-World War I contemporaries, sought to establish a new style that could represent modern times just as Classical. He created an influential twentieth-century architectural style, stated with clarity and simplicity. His mature buildings made use of materials such as industrial steel. He strove toward an architecture with a framework of structural order balanced against the implied freedom of unobstructed free-flowing open space. He called his buildings skin and bones architecture and he sought an objective approach that would guide the creative process of architectural design, but he was always concerned with expressing the spirit of the modern era. He is often associated with his quotation of the aphorisms, less is more, Mies was born March 27,1886 in Aachen, Germany. He worked in his fathers stone carving shop and at several design firms before he moved to Berlin. Mies served as manager of the Embassy of the German Empire in Saint Petersburg under Behrens. His talent was recognized and he soon began independent commissions. He began his independent professional career designing upper-class homes, joining the movement seeking a return to the purity of early 19th-century Germanic domestic styles and he rejected the eclectic and cluttered classical styles so common at the turn of the 20th century as irrelevant to the modern times. In 1913, Mies married Adele Auguste Bruhn, the daughter of a wealthy industrialist, during his military service in 1917, Mies fathered a son out of wedlock. In 1925 Mies began a relationship with designer Lilly Reich that ended when he moved to the United States, from 1940 until his death, artist Lora Marx was his primary companion. Mies carried on a relationship with sculptor and art collector Mary Callery for whom he designed an artists studio in Huntington, Long Island. He also was rumored to have a relationship with Edith Farnsworth. Mariannes son Dirk Lohan studied under, and later worked for, after World War I, Mies began, while still designing traditional neoclassical homes, a parallel experimental effort. He joined his avant-garde peers in the search for a new style that would be suitable for the modern industrial age
7.
Germany
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Germany, officially the Federal Republic of Germany, is a federal parliamentary republic in central-western Europe. It includes 16 constituent states, covers an area of 357,021 square kilometres, with about 82 million inhabitants, Germany is the most populous member state of the European Union. After the United States, it is the second most popular destination in the world. Germanys capital and largest metropolis is Berlin, while its largest conurbation is the Ruhr, other major cities include Hamburg, Munich, Cologne, Frankfurt, Stuttgart, Düsseldorf and Leipzig. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity, a region named Germania was documented before 100 AD. During the Migration Period the Germanic tribes expanded southward, beginning in the 10th century, German territories formed a central part of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation, in 1871, Germany became a nation state when most of the German states unified into the Prussian-dominated German Empire. After World War I and the German Revolution of 1918–1919, the Empire was replaced by the parliamentary Weimar Republic, the establishment of the national socialist dictatorship in 1933 led to World War II and the Holocaust. After a period of Allied occupation, two German states were founded, the Federal Republic of Germany and the German Democratic Republic, in 1990, the country was reunified. In the 21st century, Germany is a power and has the worlds fourth-largest economy by nominal GDP. As a global leader in industrial and technological sectors, it is both the worlds third-largest exporter and importer of goods. Germany is a country with a very high standard of living sustained by a skilled. It upholds a social security and universal health system, environmental protection. Germany was a member of the European Economic Community in 1957. It is part of the Schengen Area, and became a co-founder of the Eurozone in 1999, Germany is a member of the United Nations, NATO, the G8, the G20, and the OECD. The national military expenditure is the 9th highest in the world, the English word Germany derives from the Latin Germania, which came into use after Julius Caesar adopted it for the peoples east of the Rhine. This in turn descends from Proto-Germanic *þiudiskaz popular, derived from *þeudō, descended from Proto-Indo-European *tewtéh₂- people, the discovery of the Mauer 1 mandible shows that ancient humans were present in Germany at least 600,000 years ago. The oldest complete hunting weapons found anywhere in the world were discovered in a mine in Schöningen where three 380, 000-year-old wooden javelins were unearthed
8.
1929 Barcelona International Exposition
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The 1929 Barcelona International Exposition was the second World Fair to be held in Barcelona, the first one being in 1888. It took place from 20 May 1929 to 15 January 1930 in Barcelona, Catalonia and it was held on Montjuïc, the hill overlooking the harbor, southwest of the city center, and covered an area of 118 hectares at an estimated cost of 130 million pesetas. Twenty European nations participated in the fair, including Germany, Britain, Belgium, Denmark, France, Hungary, Italy, Norway, Romania, in addition, private organizations from the United States and Japan participated. Latin American countries as well as the United States were represented in the Ibero-Americana section in Sevilla, a new exposition was proposed to highlight the citys further technological progress and increase awareness abroad of modern Catalan industry. This new exhibition required the planning of Montjuïc and its adjacent areas. The exposition called for a deal of urban development within the city. At a local level, this meant the consolidation of Noucentisme, the idea of a new exhibition began to take shape in 1905, promoted by the architect Josep Puig i Cadafalch, as a way of bringing out the new Plan of links designed by Léon Jaussely. It was initially proposed that the Exposition should be constructed in the area of the Besòs River, while originally planned for 1917, the exposition was delayed due to World War I. In 1915, the committee presented a first draft by Puig i Cadafalch, the principal difficulty of the project was the amount of land required. The exposition would need at least 110 hectares, and the Barcelona City Council had only 26 by 1914, thus, using an 1879 law, they resorted to land-expropriation. In 1917, development work began at Montjuïc, with assistant engineer Marià Rubio i Bellver, landscaping was done by Jean-Claude Nicolas Forestier, who was assisted by Maria Rubio i Tudurí Nicolau. Their design was distinctly Mediterranean, with influences, combining the gardens with the construction of pergolas. Likewise, a funicular was built to access to the top of the mountain, as well as an aerial tram. However, the tram did not open until 1931, after the fair was closed. Also, the delay made obsolete the goal of promoting electrical industry, the change of objective led to the reorganization of the exhibition, so that it was devoted to three aspects, industry, the sports, and art. In this new period, the fell into the hands of Pere Domènech i Roura, the Marquis de Foronda. Despite this diversity, most buildings—at least the official ones—had a common theme of monumentality and grandiosity and this particularly included Art Deco and rationalism. The exposition was opened by King Alfonso XIII on 19 May 1929, in terms of cost, the exhibition lost money, with a deficit of 180 million pesetas
9.
Modern architecture
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Modern architecture or modernist architecture is a term applied to a group of styles of architecture which emerged in the first half of the 20th century and became dominant after World War II. The revolution in materials came first, with the use of cast iron, plate glass, the cast plate glass process was invented in 1848, allowing the manufacture of very large windows. The Crystal Palace by Joseph Paxton at the Great Exhibition of 1851 was an example of iron and plate glass construction, followed in 1864 by the first glass. These developments together led to the first steel-framed skyscraper, the ten-story Home Insurance Building in Chicago, the iron frame construction of the Eiffel Tower, then the tallest structure in the world, captured the imagination of millions of visitors to the 1889 Paris Universal Exposition. French industrialist François Coignet was the first to use iron-reinforced concrete, in 1853 Coignet built the first iron reinforced concrete structure, a four story house in the suburbs of Paris. Another important technology for the new architecture was electric light, which reduced the inherent danger of fires caused by gas in the 19th century. This break with the past was particularly urged by the architectural theorist, for each function its material, for each material its form and its ornament. This book influenced a generation of architects, including Louis Sullivan, Victor Horta, Hector Guimard, at the end of the 19th century, a few architects began to challenge the traditional Beaux Arts and Neoclassical styles that dominated architecture in Europe and the United States. The Glasgow School of Art 1896-99) designed by Charles Rennie MacIntosh, had a facade dominated by large bays of windows. The Art Nouveau style was launched in the 1890s by Victor Horta in Belgium and Hector Guimard in France, it introduced new styles of decoration, based on vegetal and floral forms. In 1903-1904 in Paris Auguste Perret and Henri Sauvage began to use reinforced concrete, previously used for industrial structures. Between 1910 and 1913, Auguste Perret built the Théâtre des Champs-Élysées, because of the concrete construction, no columns blocked the spectators view of the stage. Otto Wagner, in Vienna, was another pioneer of the new style, in his book Moderne Arkchtekture he had called for a more rationalist style of architecture, based on modern life. Wagner declared his intention to express the function of the building in its exterior, the reinforced concrete exterior was covered with plaques of marble attached with bolts of polished aluminum. The interior was purely functional and spare, an open space of steel, glass. The Viennese architect Adolf Loos also began removing any ornament from his buildings and his Steiner House, in Vienna, was an example of what he called rationalist architecture, it had a simple stucco rectangual facade with square windows and no ornament. The fame of the new movement, which known as the Vienna Secession spread beyond Austria. Josef Hoffmann, a student of Wagner, constructed a landmark of early modernist architecture and this residence, built of brick covered with Norwegian marble, was composed of geometric blocks, wings and a tower
10.
Marble
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Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Geologists use the marble to refer to metamorphosed limestone, however. Marble is commonly used for sculpture and as a building material and this stem is also the basis for the English word marmoreal, meaning marble-like. In Hungarian it is called márvány, Marble is a rock resulting from metamorphism of sedimentary carbonate rocks, most commonly limestone or dolomite rock. Metamorphism causes variable recrystallization of the carbonate mineral grains. The resulting marble rock is composed of an interlocking mosaic of carbonate crystals. Primary sedimentary textures and structures of the carbonate rock have typically been modified or destroyed. Pure white marble is the result of metamorphism of a very pure limestone or dolomite protolith, green coloration is often due to serpentine resulting from originally magnesium-rich limestone or dolostone with silica impurities. These various impurities have been mobilized and recrystallized by the intense pressure, examples of historically notable marble varieties and locations, White marble has been prized for its use in sculptures since classical times. This preference has to do with its softness, which made it easier to carve, relative isotropy and homogeneity, construction marble is a stone which is composed of calcite, dolomite or serpentine which is capable of taking a polish. More generally in construction, specifically the dimension stone trade, the marble is used for any crystalline calcitic rock useful as building stone. For example, Tennessee marble is really a dense granular fossiliferous gray to pink to maroon Ordovician limestone that geologists call the Holston Formation. Ashgabat, the city of Turkmenistan, was recorded in the 2013 Guinness Book of Records as having the worlds highest concentration of white marble buildings. According to the United States Geological Survey, U. S. domestic marble production in 2006 was 46,400 tons valued at about $18.1 million, compared to 72,300 tons valued at $18.9 million in 2005. Crushed marble production in 2006 was 11.8 million tons valued at $116 million, of which 6.5 million tons was finely ground calcium carbonate and the rest was construction aggregate. For comparison,2005 crushed marble production was 7.76 million tons valued at $58.7 million, of which 4.8 million tons was finely ground calcium carbonate, U. S. dimension marble demand is about 1.3 million tons. The DSAN World Demand for Marble Index has shown a growth of 12% annually for the 2000–2006 period, the largest dimension marble application is tile. In 1998, marble production was dominated by 4 countries that accounted for almost half of production of marble
11.
Onyx
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Onyx is a banded variety of the oxide mineral chalcedony. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands, agate has curved bands, the colors of its bands range from white to almost every color. Commonly, specimens of onyx contain bands of black and/or white, onyx comes through Latin, from the Greek ὄνυξ, meaning claw or fingernail. With its fleshtone color, onyx can be said to resemble a fingernail, the English word nail is cognate with the Greek word. Onyx is formed of bands of chalcedony in alternating colors and it is cryptocrystalline, consisting of fine intergrowths of the silica minerals quartz and moganite. Its bands are parallel to one another, as opposed to the more chaotic banding that often occurs in agates, sardonyx is a variant in which the colored bands are sard rather than black. Black onyx is perhaps the most famous variety, but is not as common as onyx with colored bands, artificial treatments have been used since ancient times to produce both the black color in black onyx and the reds and yellows in sardonyx. Most black onyx on the market is artificially colored, the name has sometimes been used, incorrectly, to label other banded lapidary materials, such as banded calcite found in Mexico, Pakistan, and other places, and often carved, polished and sold. This material is softer than true onyx, and much more readily available. The majority of carved items sold as onyx today are this carbonate material, artificial onyx types have also been produced from common chalcedony and plain agates. The first-century naturalist Pliny the Elder described these techniques being used in Roman times and these techniques are still used, as well as other dyeing treatments, and most so-called black onyx sold is artificially treated. In addition to dye treatments, heating and treatment with nitric acid have been used to lighten or eliminate undesirable colors and it has a long history of use for hardstone carving and jewelry, where it is usually cut as a cabochon or into beads. It has also used for intaglio and hardstone cameo engraved gems. Some onyx is natural but much of the material in commerce is produced by the staining of agate, onyx was used in Egypt as early as the Second Dynasty to make bowls and other pottery items. Use of sardonyx appears in the art of Minoan Crete, notably from the archaeological recoveries at Knossos, Brazilian green onyx was often used as plinths for art deco sculptures created in the 1920s and 1930s. The German sculptor Ferdinand Preiss used Brazilian green onyx for the base on the majority of his chryselephantine sculptures, green onyx was also used for trays and pin dishes – produced mainly in Austria – often with small bronze animals or figures attached. Onyx is mentioned in the Bible many times, sardonyx is mentioned in the Bible as well. Onyx was known to the Ancient Greeks and Romans, the first-century naturalist Pliny the Elder described both type of onyx and various artificial treatment techniques in his Naturalis Historia
12.
Travertine
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Travertine is a form of limestone deposited by mineral springs, especially hot springs. Travertine often has a fibrous or concentric appearance and exists in white, tan, cream-colored and it is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. In the latter, it can form stalactites, stalagmites, and it is frequently used in Italy and elsewhere as a building material. Travertine is a sedimentary rock, formed by the precipitation of carbonate minerals from solution in ground and surface waters. Similar deposits formed from water are known as tufa. The word travertine is derived from the Italian travertino, itself a derivation of the Latin tiburtinus ‘of Tibur’ and its namesake is also the origin of Tivoli, a district near Rome. Modern travertine is formed from geothermally heated supersaturated alkaline waters, with raised pCO2, on emergence, waters degas CO2 due to the lower atmospheric pCO2, resulting in an increase in pH. Since carbonate solubility decreases with increased pH, precipitation is induced, precipitation may be enhanced by factors leading to a reduction in pCO2, for example increased air-water interactions at waterfalls may be important, as may photosynthesis. Precipitation may also be enhanced by evaporation in some springs, both calcite and aragonite are found in hot spring travertines, aragonite is preferentially precipitated when temperatures are hot, while calcite dominates when temperatures are cooler. When pure and fine, travertine is white, but often it is brown to yellow due to impurities, travertine may precipitate out directly onto rock and other inert materials as in Pamukkale or Yellowstone for example. The latter has a historic value, because it was one of the quarries that Gian Lorenzo Bernini selected material from to build the famous Colonnade of St. Peters Square in Rome in 1656-1667. Michaelangelo also chose travertine as the material for the ribs of the dome of St Peters Basilica. Travertine derives its name from the town, known as Tibur in ancient Roman times. The ancient name for the stone was lapis tiburtinus, meaning tibur stone, detailed studies of the Tivoli and Guidonia travertine deposits revealed diurnal and annual rhythmic banding and laminae, which have potential use in geochronology. Cascades of natural lakes formed behind travertine dams can be seen in Pamukkale, Turkey, in Central Europes last post-glacial palaeoclimatic optimum, huge deposits of tufa formed from karst springs. On a smaller scale, these karst processes are still working, travertine has been an important building material since the Middle Ages. Travertine has formed sixteen huge, natural dams in a valley in Croatia known as Plitvice Lakes National Park, clinging to moss and rocks in the water, the travertine has built up over several millennia to form waterfalls up to 70 m in height. In the U. S. the most well-known place for travertine formation is Yellowstone National Park, Oklahoma has two parks dedicated to this natural wonder
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