Marble

Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated, although there are exceptions. In geology, the term "marble" refers to metamorphosed limestone, but its use in stonemasonry more broadly encompasses unmetamorphosed limestone.[1] Marble is commonly used for sculpture and as a building material.

Taj Mahal in March 2004
The Taj Mahal is entirely clad in marble.

Etymology

Car of history
Carlo Franzoni's sculptural marble chariot clock, the Car of History, depicting Clio, the Greek muse of history.

The word "marble" derives from the Ancient Greek μάρμαρον (mármaron),[2] from μάρμαρος (mármaros), "crystalline rock, shining stone",[3][4] perhaps from the verb μαρμαίρω (marmaírō), "to flash, sparkle, gleam";[5] R. S. P. Beekes has suggested that a "Pre-Greek origin is probable".[6]

Catedraldemarmol
Folded and weathered marble at General Carrera Lake, Chile

This stem is also the ancestor of the English word "marmoreal", meaning "marble-like." While the English term "marble" resembles the French marbre, most other European languages (with words like "marmoreal") more closely resemble the original Ancient Greek.

Physical origins

Marble is a rock resulting from metamorphism of sedimentary carbonate rocks, most commonly limestone or dolomite rock. Metamorphism causes variable recrystallization of the original carbonate mineral grains. The resulting marble rock is typically composed of an interlocking mosaic of carbonate crystals. Primary sedimentary textures and structures of the original carbonate rock (protolith) have typically been modified or destroyed.

Pure white marble is the result of metamorphism of a very pure (silicate-poor) limestone or dolomite protolith. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, iron oxides, or chert which were originally present as grains or layers in the limestone. Green coloration is often due to serpentine resulting from originally magnesium-rich limestone or dolomite with silica impurities. These various impurities have been mobilized and recrystallized by the intense pressure and heat of the metamorphism.

Types

Examples of historically notable marble varieties and locations:

Marble Color Location Country
Pentelic marble[7] pure-white, fine-grained semitranslucent Mount Pentelicus (Πεντελικό όρος), Attica (Ἀττική) Greece
Creole marble white and blue/black Pickens County, Georgia United States
Etowah marble pink, salmon, rose Pickens County, Georgia United States
Makrana marble white Makrana, Nagaur district, Rajasthan India
Murphy marble white Pickens and Gilmer Counties, Georgia United States
Nero Marquina marble black Markina, Spain Spain
Parian marble pure-white, fine-grained Island of Paros (Πάρος), South Aegean (Νοτίου Αιγαίου) Greece
Carrara marble white or blue-gray Carrara, Tuscany Italy
Ruskeala marble white near Ruskeala (Рускеала), Karelia (Карелия) Russia
Rușchița marble[8] white, pinkish, reddish Poiana Ruscă Mountains, Caraș-Severin County Romania
Bianco Sivec white near Prilep (Прилеп), Pelagonia (Пелагониски) North Macedonia
Swedish green marble green near Kolmården, Södermanland Sweden
Sylacauga marble white Talladega County, Alabama United States
Vermont marble white Proctor, Vermont United States
Yule marble uniform pure white near Marble, Colorado United States
Wunsiedel marble white Wunsiedel, Bavaria Germany

Uses

AMI - Marmoramphora
Ritual amphora of veined marble from Zakros. New palace period (1500–1450 BC), Heraklion Archaeological Museum, Crete.
Farcot and Carrier-Belleuse Conical Mystery Clock
An 1862 monumental conical pendulum clock by Eugène Farcot with a red griotte marble pedestal
Romblon island 089col
Marble Products in Romblon, Philippines.

Sculpture

White marble has been prized for its use in sculptures[9] since classical times. This preference has to do with its softness, which made it easier to carve, relative isotropy and homogeneity, and a relative resistance to shattering. Also, the low index of refraction of calcite allows light to penetrate several millimeters into the stone before being scattered out, resulting in the characteristic waxy look which gives "life" to marble sculptures of any kind, which is why many sculptors preferred and still prefer marble for sculpting.

Construction marble

Construction marble is a stone which is composed of calcite, dolomite or serpentine which is capable of taking a polish.[10] More generally in construction, specifically the dimension stone trade, the term "marble" is used for any crystalline calcitic rock (and some non-calcitic rocks) 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 capital city of Turkmenistan, was recorded in the 2013 Guinness Book of Records as having the world's highest concentration of white marble buildings.[11]

Production

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 (for aggregate and industrial uses) 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 and the rest was construction aggregate. U.S. dimension marble demand is about 1.3 million tons. The DSAN World Demand for (finished) Marble Index has shown a growth of 12% annually for the 2000–2006 period, compared to 10.5% annually for the 2000–2005 period. The largest dimension marble application is tile.

In 1998, marble production was dominated by 4 countries that accounted for almost half of world production of marble and decorative stone. Italy and China were the world leaders, each representing 16% of world production, while Spain and India produced 9% and 8%, respectively. Italy is the world leader in marble export, with 20% share in global marble production, followed by China with 16%, India with 10%, Spain with 6%, and Portugal with 5%.[12]

Occupational safety

Dust produced by cutting marble could cause lung disease but more research needs to be carried out on whether dust filters and other safety products reduce this risk.[13]

United States

The Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for marble exposure in the workplace as 15 mg/m3 total exposure and 5 mg/m3 respiratory exposure over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 10 mg/m3 total exposure and 5 mg/m3 respiratory exposure over an 8-hour workday.[14]

Degradation by acids

Acids damage marble, because the calcium carbonate in marble reacts with them, releasing carbon dioxide (technically speaking, carbonic acid, but that disintegrates quickly to CO2 and H2O) :

CaCO3(s) + 2H+(aq) → Ca2+(aq) + CO2(g) + H2O (l)

Thus, vinegar or other acidic solutions should never be used on marble. Likewise, outdoor marble statues, gravestones, or other marble structures are damaged by acid rain.

Microbial degradation

The haloalkaliphilic methylotrophic bacterium Methylophaga murata was isolated from deteriorating marble in the Kremlin.[15] Bacterial and fungal degradation was detected in four samples of marble from Milan cathedral; black Cladosporium attacked dried acrylic resin[16] using melanin.[17]

Cultural associations

Jadwiga CP
Jadwiga of Poland's sarcophagus by Antoni Madeyski, Wawel Cathedral, Cracow
Detail of Sculptural Relief on the Marble Door of the Hagia Sophia in Istanbul, Turkey
Relief on the Marble Door of the Hagia Sophia in Istanbul

As the favorite medium for Greek and Roman sculptors and architects (see classical sculpture), marble has become a cultural symbol of tradition and refined taste. Its extremely varied and colorful patterns make it a favorite decorative material, and it is often imitated in background patterns for computer displays, etc.

Places named after the stone include Marblehead, Massachusetts; Marblehead, Ohio; Marble Arch, London; the Sea of Marmara; India's Marble Rocks; and the towns of Marble, Minnesota; Marble, Colorado; Marble Falls, Texas, and Marble Hill, Manhattan, New York. The Elgin Marbles are marble sculptures from the Parthenon in Athens that are on display in the British Museum. They were brought to Britain by the Earl of Elgin.

Artificial marble

Marble dust is combined with cement or synthetic resins to make reconstituted or cultured marble. The appearance of marble can be simulated with faux marbling, a painting technique that imitates the stone's color patterns.

Gallery

Nike of Samothrake Louvre Ma2369 n4

The Nike of Samothrace is made of Parian marble (c. 220–190 BC)

Lens - Inauguration du Louvre-Lens le 4 décembre 2012, la Galerie du Temps, n° 058

The Praetorians Relief, made from grey veined marble, c. 51–52 AD

Imgp7544

Ancient marble columns in the prayer hall of the Mosque of Uqba, in Kairouan, Tunisia

2004-07-14 1880x2820 chicago aon looking up

Aon Center in Chicago was the tallest structure clad in marble upon its completion. The marble however proved to be fragile, and the building was re-clad in a similarly-colored granite at an extreme financial cost.

Cleopatra by William Wetmore Story 03

Cleopatra by William Wetmore Story was described and admired in Nathaniel Hawthorne's romance, The Marble Faun, and is on display at The Metropolitan Museum of Art in New York City.

Planalto panorama

As with many of Brazil's government buildings in Brasília, the Palácio do Planalto, official workplace of the Brazilian President, is clad in marble.

See also

References

  1. ^ Kearey, Philip (2001). Dictionary of Geology, Penguin Group, London and New York, p. 163. ISBN 978-0-14-051494-0
  2. ^ μάρμαρον, Henry George Liddell, Robert Scott, A Greek–English Lexicon, on Perseus Digital Library
  3. ^ μάρμαρος, Henry George Liddell, Robert Scott, A Greek–English Lexicon, on Perseus Digital Library
  4. ^ Marble, Compact Oxford English Dictionary. Askoxford.com. Retrieved on 2011-09-30.
  5. ^ μαρμαίρω, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus Digital Library
  6. ^ R. S. P. Beekes, Etymological Dictionary of Greek, Brill, 2009, p. 907.
  7. ^ Pentelic marble, Britannica Online Encyclopaedia. Britannica.com. Retrieved on 2011-09-30.
  8. ^ "RAPORT DE ȚARĂ. Domul din Milano a fost reconstruit cu marmură de Rușchița".
  9. ^ PROCEEDINGS 4th International Congress on “Science and Technology for the Safeguard of Cultural Heritage in the Mediterranean Basin” VOL. I. Angelo Ferrari. ISBN 9788896680315.
  10. ^ Marble Institute of America pp. 223 Glossary
  11. ^ "Turkmenistan enters record books for having the most white marble buildings | World news". London: theguardian.com. 2013-05-26. Retrieved 2013-11-24.
  12. ^ Strategic positioning study of the marble branch. CEPI Brief N° 6. tunisianindustry.nat.tn
  13. ^ Foja, A.F. (1993) Marble industry: its socioeconomic, environmental and health effects among marble worker/producer households in Romblon. Philippines University Thesis. fao.org
  14. ^ "CDC – NIOSH Pocket Guide to Chemical Hazards – Marble". www.cdc.gov. Retrieved 2015-11-27.
  15. ^ Doronina NV; Li TsD; Ivanova EG; Trotsenko IuA. (2005). "Methylophaga murata sp. nov.: a haloalkaliphilic aerobic methylotroph from deteriorating marble". Mikrobiologiia. 74 (4): 511–9. PMID 16211855.
  16. ^ Cappitelli F; Principi P; Pedrazzani R; Toniolo L; Sorlini C (2007). "Bacterial and fungal deterioration of the Milan Cathedral marble treated with protective synthetic resins". Science of the Total Environment. 385 (1–3): 172–81. doi:10.1016/j.scitotenv.2007.06.022. PMID 17658586.
  17. ^ Cappitelli F; Nosanchuk JD; Casadevall A; Toniolo L; Brusetti L; Florio S,; Principi P; Borin S; Sorlini C (Jan 2007). "Synthetic consolidants attacked by melanin-producing fungi: case study of the biodeterioration of Milan (Italy) cathedral marble treated with acrylics". Applied and Environmental Microbiology. 73 (1): 271–7. doi:10.1128/AEM.02220-06. PMC 1797126. PMID 17071788.

External links

Alice Marble

Alice Marble (September 28, 1913 – December 13, 1990) was an American tennis player who won 18 Grand Slam championships (1936–40): five in singles, six in women's doubles, and seven in mixed doubles.

Bust (sculpture)

A bust is a sculpted or cast representation of the upper part of the human figure, depicting a person's head and neck, and a variable portion of the chest and shoulders. The piece is normally supported by a plinth. The bust is generally a portrait intended to record the appearance of an individual, but may sometimes represent a type. They may be of any medium used for sculpture, such as marble, bronze, terracotta, wax or wood.

Carrara marble

Carrara marble is a type of white or blue-grey marble popular for use in sculpture and building decor. It is quarried in the city of Carrara located in the province of Massa and Carrara in the Lunigiana, the northernmost tip of modern-day Tuscany, Italy.

Connie Willis

Constance Elaine Trimmer Willis (born December 31, 1945), commonly known as Connie Willis, is an American science fiction and fantasy writer. She has won eleven Hugo Awards and seven Nebula Awards for particular works—more major awards than any other writer—most recently the "Best Novel" Hugo and Nebula Awards for Blackout/All Clear (2010). She was inducted by the Science Fiction Hall of Fame in 2009 and the Science Fiction Writers of America named her its 28th SFWA Grand Master in 2011.Several of her works feature time travel by history students at a faculty of the future University of Oxford—sometimes called the Time Travel series. They are the short story "Fire Watch" (1982, also in several anthologies and the 1985 collection of the same name), the novels Doomsday Book and To Say Nothing of the Dog (1992 and 1997), as well as the two-part novel Blackout/All Clear (2010). All four won the annual Hugo Award but Doomsday Book and Blackout/All Clear won both the Hugo and Nebula Awards.

David (Michelangelo)

David is a masterpiece of Renaissance sculpture created in marble between 1501 and 1504 by the Italian artist Michelangelo. David is a 5.17-metre (17.0 ft) marble statue of the Biblical hero David, a favoured subject in the art of Florence.David was originally commissioned as one of a series of statues of prophets to be positioned along the roofline of the east end of Florence Cathedral, but was instead placed in a public square, outside the Palazzo Vecchio, the seat of civic government in Florence, in the Piazza della Signoria where it was unveiled on 8 September 1504. The statue was moved to the Galleria dell'Accademia, Florence, in 1873, and later replaced at the original location by a replica.

Because of the nature of the hero it represented, the statue soon came to symbolize the defence of civil liberties embodied in the Republic of Florence, an independent city-state threatened on all sides by more powerful rival states and by the hegemony of the Medici family. The eyes of David, with a warning glare, were turned towards Rome.

Gian Lorenzo Bernini

Gian Lorenzo Bernini (Italian pronunciation: [ˈdʒan loˈrɛntso berˈniːni]; also Gianlorenzo or Giovanni Lorenzo; 7 December 1598 – 28 November 1680) was an Italian sculptor and architect. While a major figure in the world of architecture, he was, also and even more prominently, the leading sculptor of his age, credited with creating the Baroque style of sculpture. As one scholar has commented, "What Shakespeare is to drama, Bernini may be to sculpture: the first pan-European sculptor whose name is instantaneously identifiable with a particular manner and vision, and whose influence was inordinately powerful...." In addition, he was a painter (mostly small canvases in oil) and a man of the theater: he wrote, directed and acted in plays (mostly Carnival satires), for which he designed stage sets and theatrical machinery. He produced designs as well for a wide variety of decorative art objects including lamps, tables, mirrors, and even coaches.

As architect and city planner, he designed secular buildings, churches, chapels, and public squares, as well as massive works combining both architecture and sculpture, especially elaborate public fountains and funerary monuments and a whole series of temporary structures (in stucco and wood) for funerals and festivals. His broad technical versatility, boundless compositional inventiveness and sheer skill in manipulating marble ensured that he would be considered a worthy successor of Michelangelo, far outshining other sculptors of his generation. His talent extended beyond the confines of sculpture to a consideration of the setting in which it would be situated; his ability to synthesize sculpture, painting, and architecture into a coherent conceptual and visual whole has been termed by the late art historian Irving Lavin the "unity of the visual arts".

Greater Austin

Austin–Round Rock is a five-county metropolitan area in the U.S. state of Texas, as defined by the Office of Management and Budget. Commonly referred to as Greater Austin, the metropolitan area is situated in Central Texas on the eastern edge of the American Southwest, and borders San Antonio–New Braunfels to the south.

Austin–Round Rock is the 30th largest metropolitan area in the United States, with a population of 2,168,316 people and 16th largest GDP per Capita as of the 2018 U.S. census estimate. The metropolitan area is centered on the City of Austin—the fourth-largest city in Texas and the 11th-largest city in the United States with a population of 950,715 people. Austin's largest suburbs are Round Rock, Cedar Park, Georgetown, San Marcos and Pflugerville.

Marble (toy)

A marble is a small spherical toy often made from glass, clay, steel, plastic or agate. These balls vary in size. Most commonly, they are about 1 cm (1⁄2 in) in diameter, but they may range from less than 1 mm (1⁄30 in) to over 8 cm (3 in), while some art glass marbles for display purposes are over 30 cm (12 in) wide. Marbles can be used for a variety of games called marbles. They are often collected, both for nostalgia and for their aesthetic colors. In the North of England the objects and the game are called "taws", with larger taws being called bottle washers after the use of a marble in Codd-neck bottles, which were often collected for play.

Marble Arch

Marble Arch is a 19th-century white marble-faced triumphal arch in London, England. The structure was designed by John Nash in 1827 to be the state entrance to the cour d'honneur of Buckingham Palace; it stood near the site of what is today the three-bayed, central projection of the palace containing the well known balcony. In 1851 on the initiative of architect and urban planner, Decimus Burton, one time pupil of John Nash, it was relocated and following the widening of Park Lane in the early 1960s to where it is now sited, incongruently isolated, on a large traffic island at the junction of Oxford Street, Park Lane and Edgware Road. Admiralty Arch, Holyhead in Wales is a similar arch, even more so cut off from public access, at the other end of the A5.

Only members of the Royal Family and the King's Troop, Royal Horse Artillery are said to be permitted to pass through the arch; this happens in ceremonial processions.The arch gives its name to the area surrounding it, particularly the southern portion of Edgware Road and also to the underground station. The arch is not part of the Royal Parks and is local authority maintained.

Marble Arch Caves

The Marble Arch Caves are a series of natural limestone caves located near the village of Florencecourt in County Fermanagh, Northern Ireland. The caves are named after the nearby Marble Arch, a natural limestone arch at the upstream end of Cladagh Glen under which the Cladagh River flows.

The caves are formed from three rivers draining off the northern slopes of Cuilcagh mountain, which combine underground to form the Cladagh. On the surface, the river emerges from the largest karst resurgence in Ireland, and one of the largest in the United Kingdom.

At 11.5 kilometres (7.1 mi) the Marble Arch Caves form the longest known cave system in Northern Ireland, and the karst is considered to be among the finest in the British Isles.

Marble Hill, Manhattan

Marble Hill is the northernmost neighborhood in the New York City borough of Manhattan. It is the only Manhattan neighborhood that is not on an island. Marble Hill was occupied as a Dutch colonial settlement in 1646, and gained its current name in 1891 because of marble deposits underneath the neighborhood.

Politically a part of Manhattan and New York County, Marble Hill became an island in the Harlem River when it was separated from the island of Manhattan by the construction of the Harlem Ship Canal in 1895. In 1914, the Harlem River was filled in on the north side of Marble Hill, connecting it to the North American mainland and the Bronx. Because of this change in geography, Marble Hill is often associated with the Bronx and is part of Bronx Community District 8. In addition, Marble Hill has a Bronx ZIP Code of 10463, and is patrolled by the New York City Police Department's 50th Precinct, headquartered in the Bronx.

Marble Hill House

Marble Hill House is a Palladian villa built between 1724 and 1729 in Twickenham in the London Borough of Richmond upon Thames. It was the home of Henrietta Howard, Countess of Suffolk, who lived there until her death. The compact design soon became famous and furnished a standard model for the Georgian English villa and for plantation houses in the American colonies.

Marble Madness

Marble Madness is an arcade video game designed by Mark Cerny and published by Atari Games in 1984. The player uses a trackball to guide an onscreen marble through six obstacle-filled courses within a time limit. Marble Madness was Atari's first game to use the Atari System 1 hardware and to be programmed in the C programming language. It was also one of the first games to use true stereo sound; previous games used either monaural sound or simulated stereo.

Cerny drew inspiration from miniature golf, racing games, and artwork by M. C. Escher. He applied a minimalist approach in designing the appearance of the game's courses and enemies.

Marble Madness was commercially successful. The game was ported to numerous platforms and inspired the development of other games. A sequel was developed and planned for release in 1991 but canceled when location testing showed the game could not compete with other titles.

Marble Mountain Wilderness

The Marble Mountain Wilderness is a 241,744-acre (978.30 km2) wilderness area located 60 miles (97 km) southwest of Yreka, California, in the United States. It is managed by the United States Forest Service and is within the Klamath National Forest in Siskiyou County. The land was first set aside on April 1931 as the Marble Mountain Primitive Area, which comprised 234,957 acres (950.84 km2). It was one of four areas to gain primitive status under the Forest Service's L-20 regulations that year. In 1964, it became a federally designated wilderness area when the U.S. Congress passed the Wilderness Act.

The name comes from the distinctive coloration caused by light-colored limestone along with black metamorphic rock on some peaks, giving the mountains a marbled appearance. There are at least five different rock types identified here.

The wilderness is in the Klamath Mountains geomorphic province (a large area having similar features such as terrain and geology). The horseshoe-shaped Salmon Mountains are at the core of the wilderness with Marble Mountain being a north-trending spur ridge of the Salmons. The highest point in the Marbles is Boulder Peak at 8,299 feet (2,530 m).

Pietà (Michelangelo)

The Pietà (Italian: [pjeˈta]; English: "The Pity"; 1498–1499) is a work of Renaissance sculpture by Michelangelo Buonarroti, housed in St. Peter's Basilica, Vatican City. It is the first of a number of works of the same theme by the artist. The statue was commissioned for the French Cardinal Jean de Bilhères, who was a representative in Rome. The sculpture, in Carrara marble, was made for the cardinal's funeral monument, but was moved to its current location, the first chapel on the right as one enters the basilica, in the 18th century. It is the only piece Michelangelo ever signed.

This famous work of art depicts the body of Jesus on the lap of his mother Mary after the Crucifixion. The theme is of Northern origin. Michelangelo's interpretation of the Pietà is unprecedented in Italian sculpture. It is an important work as it balances the Renaissance ideals of classical beauty with naturalism.

Quarry

A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground.

The word quarry can also include the underground quarrying for stone, such as Bath stone.

Taj Mahal

The Taj Mahal (; Hindi: ताज महल [taːdʒ ˈmɛːɦ(ə)l], meaning "Crown of the Palaces") is an ivory-white marble mausoleum on the south bank of the Yamuna river in the Indian city of Agra. It was commissioned in 1632 by the Mughal emperor, Shah Jahan (reigned from 1628 to 1658), to house the tomb of his favourite wife, Mumtaz Mahal. It also houses the tomb of Shah Jahan, the builder. The tomb is the centerpiece of a 17-hectare (42-acre) complex, which includes a mosque and a guest house, and is set in formal gardens bounded on three sides by a crenellated wall.

Construction of the mausoleum was essentially completed in 1643 but work continued on other phases of the project for another 10 years. The Taj Mahal complex is believed to have been completed in its entirety in 1653 at a cost estimated at the time to be around 32 million rupees, which in 2015 would be approximately 52.8 billion rupees (U.S. $827 million). The construction project employed some 20,000 artisans under the guidance of a board of architects led by the court architect to the emperor, Ustad Ahmad Lahauri.

The Taj Mahal was designated as a UNESCO World Heritage Site in 1983 for being "the jewel of Muslim art in India and one of the universally admired masterpieces of the world's heritage". It is regarded by many as the best example of Mughal architecture and a symbol of India's rich history. The Taj Mahal attracts 7–8 million visitors a year and in 2007, it was declared a winner of the New7Wonders of the World (2000–2007) initiative.

The Blue Marble

The Blue Marble is an image of Earth taken on December 7, 1972, from a distance of about 29,000 kilometers (18,000 miles) from the planet's surface. It was taken by the crew of the Apollo 17 spacecraft on its way to the Moon, and is one of the most reproduced images in history.The image has the official NASA designation AS17-148-22727 and mainly shows the Earth from the Mediterranean Sea to Antarctica. This was the first time the Apollo trajectory made it possible to photograph the south polar ice cap, despite the Southern Hemisphere being heavily covered in clouds. In addition to the Arabian Peninsula and Madagascar, almost the entire coastline of Africa is clearly visible. The Asian mainland is on the horizon.

NASA has also applied the name to a 2012 series of images which cover the entire globe at relatively high resolution. These were created by looking through satellite-pictures taken over time in order to find as many cloudless photographs as possible to use in the final images.

Washington Monument

The Washington Monument is an obelisk on the National Mall in Washington, D.C., built to commemorate George Washington, once commander-in-chief of the Continental Army and the first President of the United States. Located almost due east of the Reflecting Pool and the Lincoln Memorial, the monument, made of marble, granite, and bluestone gneiss, is both the world's tallest predominantly stone structure and the world's tallest obelisk, standing 554 feet 7 11⁄32 inches (169.046 m) tall according to the National Geodetic Survey (measured 2013–14) or 555 feet 5 1⁄8 inches (169.294 m) tall according to the National Park Service (measured 1884). It is the tallest monumental column in the world if all are measured above their pedestrian entrances. It was the tallest structure in the world from 1884 to 1889, when it was overtaken by the Eiffel Tower in Paris.

Construction of the monument began in 1848 and was halted from 1854 to 1877 due to a lack of funds, a struggle for control over the Washington National Monument Society, and the intervention of the American Civil War. Although the stone structure was completed in 1884, internal ironwork, the knoll, and other finishing touches were not completed until 1888. A difference in shading of the marble, visible approximately 150 feet (46 m) or 27% up, shows where construction was halted and later resumed with marble from a different source. The original design was by Robert Mills, but he did not include his proposed colonnade due to a lack of funds, proceeding only with a bare obelisk. The cornerstone was laid on July 4, 1848; the first stone was laid atop the unfinished stump on August 7, 1880; the capstone was set on December 6, 1884; the completed monument was dedicated on February 21, 1885; and officially opened October 9, 1888.

The Washington Monument is a hollow Egyptian style stone obelisk with a 500-foot (152.4 m) tall column and a 55-foot (16.8 m) tall pyramidion. Its walls are 15 feet (4.6 m) thick at its base and 1 1⁄2 feet (0.46 m) thick at their top. The marble pyramidion has thin walls only 7 inches (18 cm) thick supported by six arches, two between opposite walls that cross at the center of the pyramidion and four smaller corner arches. The top of the pyramidion is a large marble capstone with a small aluminum pyramid at its apex with inscriptions on all four sides. The lowest 150 feet (45.7 m) of the walls, constructed during the first phase 1848–1854, are composed of a pile of bluestone gneiss rubble stones (not finished stones) held together by a large amount of mortar with a facade of semi-finished marble stones about 1 1⁄4 feet (0.4 m) thick. The upper 350 feet (106.7 m) of the walls, constructed during the second phase 1880–1884, are composed of finished marble surface stones, half of which project into the walls, partially backed by finished granite stones.The interior is occupied by iron stairs that spiral up the walls, with an elevator in the center, each supported by four iron columns, which do not support the stone structure. The stairs contain fifty sections, most on the north and south walls, with many long landings stretching between them along the east and west walls. These landings allowed many inscribed memorial stones of various materials and sizes to be easily viewed while the stairs were accessible (until 1976), plus one memorial stone between stairs that is difficult to view. The pyramidion has eight observation windows, two per side, and eight red aircraft warning lights, two per side. Two aluminum lightning rods connected via the elevator support columns to ground water protect the monument. The monument's present foundation is 37 feet (11.3 m) thick, consisting of half of its original bluestone gneiss rubble encased in concrete. At the northeast corner of the foundation, 21 feet (6.4 m) below ground, is the marble cornerstone, including a zinc case filled with memorabilia. Fifty American flags fly 24 hours a day on a large circle of flag poles centered on the monument. In 2001, a temporary screening facility was added to the entrance to prevent a terrorist attack. In 2011, an earthquake slightly damaged the monument, mostly the pyramidion.

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