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16-499: The modern name for the hill was given by early English colonists who, while sailing along the coastline, noticed the bluish hue of the exposed granite faces when viewed from a distance (due to Riebeckite ). The Blue Hills' eastern slopes face the ocean and lie within Quincy . The area once attracted quarrying for its "blue granite". Great Blue Hill was a point of reference for the Indians, and

32-622: Is 5.0–6.0, and its specific gravity is 3.0–3.4. Cleavage is perfect, two directions in the shape of a diamond ; fracture is uneven, splintery. It is often translucent to nearly opaque. Riebeckite was first described in 1888 for an occurrence on Socotra Island , Aden Governorate, Yemen , and named for German explorer Emil Riebeck (1853–1885). The mineral is also known as crocidolite . Riebeckite typically forms dark-blue elongated to fibrous crystals in highly alkali granites , syenites , rarely in felsic volcanics , granite pegmatites and schist . It occurs in banded iron formations as

48-413: Is a sodium -rich member of the amphibole group of silicate minerals , chemical formula Na 2 (Fe 3 Fe 2 )Si 8 O 22 (OH) 2 . It forms a solid solution series with magnesioriebeckite. It crystallizes in the monoclinic system, usually as long prismatic crystals showing a diamond-shaped cross section, but also in fibrous, bladed, acicular, columnar, and radiating forms. Its Mohs hardness

64-593: Is the highest point in Greater Boston and Norfolk County and also the highest within 10 miles of the Atlantic coast south of central Maine . For this reason, American meteorologist Abbott Lawrence Rotch chose Great Blue Hill as the site for an observatory, which became known as the Blue Hill Meteorological Observatory after its completion in 1885. Rotch conducted ground-breaking studies of

80-485: The Lorillard Tobacco Company (now part of the R. J. Reynolds Tobacco Company ). Blue asbestos was also used to similar effect, and hazard, in early gas masks. Monoclinic In crystallography , the monoclinic crystal system is one of the seven crystal systems . A crystal system is described by three vectors . In the monoclinic system, the crystal is described by vectors of unequal lengths, as in

96-418: The asbestiform variety crocidolite (blue asbestos ). It occurs in association with aegirine , nepheline , albite , arfvedsonite in igneous rocks ; with tremolite , ferro- actinolite in metamorphic rocks ; and with grunerite , magnetite , hematite , stilpnomelane , ankerite , siderite , calcite , chalcedonic quartz in iron formations. The riebeckite granite known as ailsite , found on

112-423: The orthorhombic system. They form a parallelogram prism . Hence two pairs of vectors are perpendicular (meet at right angles), while the third pair makes an angle other than 90°. Two monoclinic Bravais lattices exist: the primitive monoclinic and the base-centered monoclinic. For the base-centered monoclinic lattice, the primitive cell has the shape of an oblique rhombic prism; it can be constructed because

128-569: The atmosphere at Blue Hill for many years, and meteorological data is still gathered at the site. From the Eliot Tower at the summit, the city of Boston and many of the surrounding hills of the Milton and Canton area are visible. Great Blue Hill, and the Blue Hills Reservation in general, is a popular hiking destination, valued as much for its splendid trails and views as for its proximity to

144-580: The hill as well. In 1980, the hill was the subject of a prank by WNAC-TV 's news department, where it was alleged that a volcano was erupting. Great Blue Hill and the Blue Hills Reservation is the last remaining area in Greater Boston where the timber rattlesnake and copperhead can be found. The snakes are so rare in the state that they are rarely encountered by people. They are both considered endangered, making it illegal to harass, kill, collect, or possess. Riebeckite Riebeckite

160-680: The island of Ailsa Craig in western Scotland , is prized for its use in the manufacture of curling stones. Riebeckite granite was used for the facing stones of the Canton Viaduct from Moyles Quarry (a.k.a. Canton Viaduct Quarry) now part of Borderland State Park in Massachusetts , US. The commonwealth's name is even taken from an Algonquian word for the Great Blue Hill , which got its color from this form of granite. The fibrous forms of riebeckite are known as crocidolite and are one of

176-636: The local tribe were known as the "people at the large hill" ( Massachuseuck ). The English called them the Massachusetts , which ultimately became the name of the state. The north and west sides of Great Blue Hill drain into the Neponset River , and thence into Boston Harbor . The south and east sides of Great Blue Hill drain into the Blue Hill River , thence into the Farm River , Monatiquot River , Weymouth Fore River , and into Boston Harbor. Its summit

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192-473: The metropolitan area. There is also alpine skiing available at Blue Hills Ski Area , consisting of eight trails served by a double chair and two surface lifts. Summit Road, the steep paved road that leads to the top of the hill, is closed to cars except for employees of the weather observatory. However, the road is open to hikers and cyclists. Boston public radio and television stations WGBH (FM) / WGBH-TV take their call letters from Great Blue Hill, which

208-542: The monoclinic crystal system by crystal class. It lists the International Tables for Crystallography space group numbers, followed by the crystal class name, its point group in Schoenflies notation , Hermann–Mauguin (international) notation , orbifold notation, and Coxeter notation, type descriptors, mineral examples, and the notation for the space groups . Sphenoidal is also called monoclinic hemimorphic, domatic

224-545: The six recognised types of asbestos . Often referred to as blue asbestos, it is considered the most hazardous. The association between blue asbestos and mesothelioma was established by J. C. Wagner, C. A. Sleggs, and P. Marchand by 1960. Crocidolite asbestos was mined in South Africa , Bolivia , and Wittenoom, Western Australia . Bolivian crocidolite was used in approximately 13 billion Kent Micronite cigarette filters, manufactured from March 1952 until at least May 1956 by

240-416: The two-dimensional centered rectangular base layer can also be described with primitive rhombic axes. The length a {\displaystyle a} of the primitive cell below equals 1 2 a 2 + b 2 {\displaystyle {\frac {1}{2}}{\sqrt {a^{2}+b^{2}}}} of the conventional cell above. The table below organizes the space groups of

256-548: Was the original location of the station's FM and TV transmitters. WGBH (FM) still transmits from the site, grandfathered at an effective radiated power of 98,000 watts. WGBH-TV moved its antenna to a taller tower in Needham in the 1960s. WZRM , an FM station licensed to Brockton, moved its transmitter northward from near Brockton to Great Blue Hill in 2005 to better serve Boston. The NOAA Weather Radio station serving Greater Boston and adjacent coastal waters, KHB35, transmits atop

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