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mica

mica

mica Sentence Examples

  • The mica mined in India is practically all muscovite.

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  • The mica mined in India is practically all muscovite.

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  • Mica is mined near Mrogoro.

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  • In 1870 North Carolina's mica mines were reopened, and they produce the best grade of sheet mica for glazing and a large percentage of the country's yield of this mineral.

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  • For the more delicate species, such as the Callithamnia and Ectocarpi, it is an excellent plan to place a small fruiting fragment, carefully floated out in water, on a slip of mica of the size of an ordinary microscopical slide, and allow it to dry.

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  • The phyllites (q.v.) form a middle term between this group and the slates; they consist usually of quartz, white mica and chlorite, and have much of the foliation and schistosity of the mica-schists.

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  • Deposits of copper, tin, iron and tungsten have been discovered, and a variety of other mineral products (graphite, mica, spodumene, coal, petroleum, &c.).

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  • mica, talc, chlorite, haematite), or in long blades or fibres (anthophyllite, tremolite, actinolite, tourmaline), and, when these have a well marked parallel arrangement in definite bands or folia, the rock will break far more easily along the bands than across them.

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  • These cracks coincide with planes of easy separation or of gliding in the crystal; they are especially useful in helping to determine the crystallographic orientation of a cleavage flake of mica when crystal faces are absent.

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  • In the Inikurti mine, Nellore, "books" of mica measuring 10 ft.

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  • Large beds of mica are found in the east.

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  • portion of the Mountain Region; and that mica was mined here before any European settlement of the country seems proved by numerous excavations and by huge heaps on which are large oak and chestnut trees, some fallen and decayed.

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  • In emery, magnetite in a granular form is largely associated with the corundum; and in certain kinds of mica magnetite occurs as thin dendritic enclosures.

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  • In the mica-schists of this group biotite or muscovite may be the principal mineral and often both are present in varying proportions; the mica has developed from the argillaceous matter of the original rock; in addition there is always quartz and sometimes felspar (albite or oligoclase).

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  • The quartz-schists consist of quartz and white mica, and are intimately related to quartzites.

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  • Sheets of mica which have been subjected to earth-movements are frequently cracked and ridged parallel to these directions, and are then valueless for economic purposes.

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  • The plane of the optic axes may be either perpendicular or parallel to the plane of symmetry of the crystal, and according to its position two classes of mica are distinguished.

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  • Garnets and mica are everywhere found.

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  • Some unions annually purchase large quantities ~cono of merchandise for their members, especially chemical mica.

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  • Ordinary diatoms and desmids may be mounted on mica, as above described, by putting a portion in a vessel of water and exposing it to sunlight, when they rise to the surface, and may be thus removed comparatively free from dirt or impurity.

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  • Mica >>

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  • MICA, a group of widely distributed rock-forming minerals, some of which have important commercial applications.

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  • The name mica is probably derived from the Latin micare, to shine, to glitter; the German word glimmer has the same meaning.

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  • The different species of mica have very nearly the same forms and interfacial angles, and they not infrequently occur intergrown together in parallel position.

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  • A similar six-rayed system of cracks, bisecting the angles between the rays of the previous set, is produced when a blunt punch is gradually pressed against a sheet of mica; this is known as the "pressure figure."

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  • Inclusions of other minerals are frequently to be observed in mica.

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  • Spangles of mica are much used for decorative purposes of various kinds, and the mineral was formerly known as glacies Mariae (Ger., Frauenglas) because of its use for decorating statues of the Virgin.

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  • The lapis specularis of Pliny, scattered over the Circus Maximus to produce a shining whiteness, was probably mica.

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  • Large quantities of ground mica are used in the manufacture of wall-paper, and to produce a frosted effect on toys, stage scenery, &c. Powdered mica is also used in the manufacture of paints and paper, as a lubricant, and as an absorbent of nitro-glycerine and disinfectants.

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  • The most extensive application of mica at the present day is for electrical purposes.

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  • For various purposes a manufactured material known as "micanite" or "micanite cloth" is much used; this consists of small sheets of mica cemented with shellac or other insulating cement on cloth or paper.

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  • Many other uses of mica might be mentioned.

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  • Mica mining is an industry of considerable importance, especially in India; but here the methods of mining are very primitive and wasteful.

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  • In working downwards in open quarries and in tortuous shafts and passages much of the mica is damaged, and a large amount of labour is expended in hauling waste material to the surface.

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  • Since the mineral occurs in definite veins, a more satisfactory and economical method of working would be that adopted in metalliferous mines, with a vertical shaft, cross-cuts, and levels running along the strike of the vein: the mica could then be extracted by overhead stopping, and the waste material used for filling up the worked-out excavations.

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  • In dressing mica the "books" are split along the cleavage into sheets of the required thickness, and the sheets trimmed into rectangles with a sharp knife, shears or guillotine, stained and damaged portions being rejected.

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  • Scrap mica is ground to powder or used in the manufacture of micanite.

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  • The price of mica varies very considerably according to the size, transparency and quality of the sheets.

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  • P. Merrill, The Non-Metallic Minerals (New York, 1904), pp. 163180; "The Mining and Preparation of Mica for Commercial Purposes," Bulletin of the Imperial Institute (London, 1904), ii.

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  • Cirkel, "Mica: its Occurrence, Exploitation and Uses" (Canadian Dept.

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  • of glass or mica.

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  • The slits may be cut out of tin-plate, and half covered by mica or " microscopic glass," held in position by a little cement.

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  • It was used in windows, though by no means exclusively, mica, alabaster and shells having been also employed.

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  • Most of the island is occupied by the band of the old rocks, which include mica, glaucophane and sericite-schists and slates; there are small intrusions of granite, and numerous dikes and masses of basic eruptive rocks.

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  • four series of "Researches on Heat," in the course of which he described the polarization of heat by tourmaline, by transmission through a bundle of thin mica plates inclined to the transmitted ray, and by reflection from the multiplied surfaces of a pile of mica plates placed at the polarizing angle, and also its circular polarization by two internal reflections in rhombs of rock-salt.

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  • Within these limits are to be found most of the minerals known - gold, silver, quicksilver, copper, lead, zinc, iron, manganese, wolfram, bismuth, thorium, vanadium; mica, coal, &c. On or near the coast are coal, salt, sulphur, borax, nitrates and petroleum.

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  • Quincy granite takes a very high polish, owing to the absence of mica and to the coarser cleavage of its hornblende and augite.

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  • Silver follows gold in importance, but the other minerals met with, including gypsum, mica, petroleum, natural gas, granite, marble and tin are not found in paying quantities.

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  • Slates consist largely of thin plates of mica arranged parallel to the cleavage faces.

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  • This mica has developed in the rock as it was folded and compressed.

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  • The faces of slates have usually a slightly silky lustre due to the abundance of minute scales of mica all lying parallel and reflecting light simultaneously from their pearly basal planes.

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  • In microscopic section the best slates show much colourless mica in small, thin, irregular scales.

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  • Green chlorite is usually also abundant in flakes like those of the mica.

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  • The spots contain variety of minerals, sometimes mainly white mica or chlorite.

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  • These crystals may be half an inch to several inches in length; they are usually more or less completely weathered to white mica and kaolin.

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  • In point of absolute mass they are insignificant compared with the abundance and variety of potassiferous silicates, which occur everywhere in the earth's crust; orthoclase (potash felspar) and potash mica may be quoted as prominent examples.

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  • Along with these, similarly, hornblende and diabase occur in the Pelew Islands and gneiss and mica 1 These are dependencies of New Zealand, as are also the following islands and groups which lie apart from the main Polynesian clusters, nearer New Zealand itself: Antipodes Islands, Auckland Islands, Bounty Islands, Campbell Islands, Chatham Islands, Kermadec Islands.

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  • The Concord granite is a medium bluish-grey coloured muscovitebiotite granite, with mica plates so abundant as to effect the durability of the polish of the stone; it is used for building-the outer walls of the Library of Congress at Washington, D.C., are made of this stone-to a less degree for monuments, for which the output of one quarry is used exclusively, and for paving blocks.

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  • granites with an unusually large proportion of soda-lime feldspar), of various grey shades, sometimes tinged with blue, pink or buff, and always marked with black mica; the finer varieties take a high polish and are used for monuments, and the coarser grades are used for construction, especially of railway bridges, and for paving and curbing.

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  • Mica, first mined at grafton|Grafton, Grafton county, in 1803, found also in the northern part of Merrimack county and in the north-western corner of Cheshire county in such quantities that for sixty years:New Hampshire was the largest producer of mica in the United States, is no longer an important product: in 1907 its value ($7227) was less than that of the mica produced in South Dakota, Alabama, North Carolina or Colorado.

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  • Other minerals whose production may be found stated in detail in the annual volume on Mineral Resources of the United States Geological Survey are: natural pigments, felspar, white mica, graphite, fluorspar, arsenic, quartz, barytes, bromine.

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  • - Under the name of Aristotle, three treatises on the good of man have come down to us, Mica Nuco i tkaa (irpos NLKOµaXov, Porphyry), Howe, Eub ipta (7r Os Eiibjµov, Porphyry), and 'HBLKa µeyaXa; so like one another that there seems no tenable hypothesis except that they are the manuscript writings of one man.

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  • The card or "fly," formerly made of cardboard, now consists of a disk either of mica covered with paper or of paper alone, but in all cases the card is divided into points and degrees as shown in fig.

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  • The mica card is generally mounted on a brass framework, F F, with a brass cap, C, fitted with a sapphire centre and carrying four magnetized needles, N, N, N, N, as in fig.

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  • The card is a mica disk, either painted as in fig.

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  • S, Mica card.

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  • Gneiss & Mica Schist A-G.

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  • Just as a granite is a conglomerate or mechanical mixture of distinct crystalline grains of three perfectly definite minerals, mica, quartz, and felspar, so iron and steel in their usual slowly cooled state consist of a mixture of microscopic particles of such definite quasiminerals, diametrically unlike.

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  • The south-western part of the country, a vast and almost level plain, is known as Dar Homr. A granitic sand with abundance of mica and feldspar forms the upper stratum throughout the greater part of Kordofan; but an admixture of clay, which is observable in the north, becomes strongly marked in the south, where there are also stretches of black vegetable mould.

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  • Beneath there appears to be an unbroken surface of mica schist.

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  • The water which has found its way through the granitic sand flows over the surface of the mica schist and settles in the hollows, and by sinking wells to the solid rock a supply of water can generally be obtained.

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  • The other minerals found in the concentrates are pebbles and fragments of pyrope, zircon, cyanite, chrome-diopside, enstatite, a green pyroxene, mica, ilmenite, magnetite, chromite, hornblende, olivine, barytes, calcite and pyrites.

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  • From these rocks in the Ottawa valley are quarried or mined granite, marble, magnificent blue sodalite, felspar, talc, actinolite, mica, apatite, graphite and corundum; the latter mineral, which occurs on a larger scale here than elsewhere, is rapidly replacing emery as an abrasive.

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  • The soil of the Delta is a dark grey fine sandy soil, becoming at times almost a stiff clay by reason of the fineness of its particles, which consist almost wholly of extremely small grains of quartz with a few other minerals, and often numerous flakes of mica.

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  • The Eastern Cordillera is composed of gneiss, mica and chlorite schist and other crystalline rocks of ancient date; the Western Cordillera, on the other hand, is formed of porphyritic eruptive rocks of Mesozoic age, together with sedimentary deposits containing Cretaceous fossils.

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  • Putting aside salt, which has been already treated, the chief mining resources of India at the present day are the coal mines, the gold mines, the petroleum oil-fields, the ruby mines, manganese deposits, mica mines in Bengal, and the tin ores and jade of Burma.

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  • Mica has long been obtained in Bengal, chiefly in the Hazaribagh district, and there is a rubycoloured variety which is held in great estimation.

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  • In Madras also a mica industry has recently grown up. Tin is found in the Tavoy and Mergui districts of Lower Burma, and has for many years been worked in an unprogressive manner chiefly by Chinese labour.

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  • In other cases, Leyden jars or condensers take the form of sheets of mica or micanite or ebonite partly coated with tin foil or silver leaf on both sides; or a pile of sheets of alternate tin foil and mica may be built up, the tin foil sheets having lugs projecting out first on one side and then on the other.

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  • All the lugs on one side are connected together, and so also are all the lugs on the other side, and the two sets of tin foils separated by sheets of mica constitute the two metallic surfaces of the Leyden jar condenser.

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  • It is found in the minerals lepidolite, petalite and in various specimens of mica and of carnallite, and in some mineral waters.

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  • Iron ores are widely distributed, but have not been developed; graphite is mined in Colfax county; mica in Taos county, and to a small extent in Rio Arriba county; marble is quarried in Otero county and sandstone in Bernalillo, Colfax and San Miguel counties.

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  • The rock is a very compact and fine-grained mixture of felspar, quartz and mica, often graduating to mica schist, quartzite and gneiss.

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  • In the western and northern alpine part of Sweden, near the boundaries of Norway, the Silurian strata are covered by crystalline rocks, mica schists, quartzites, &c., of an enormous thickness, which have been brought into their present positions upon a thrust-plane.

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  • In the upper chamber, about half-way between the centre of the base and the apex, was a single skeleton, adorned with beads, copper bracelets and plates of mica; in the lower chamber, directly under the upper and partly in the natural earth, were two skeletons, one adorned with beads and the other without ornament.

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  • The primary rocks which appear at Mitushev Kamen are overlaid with thick beds of quartzites and clayslates containing sulphide of iron, with subordinate layers of talc or mica slate, and thinner beds of fossiliferous limestone, Silurian or Devonian.

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  • The Russian Altai is composed mainly of mica and chlorite schists and slates, together with beds of limestone, and in the higher horizons Devonian and Carboniferous fossils occur in many places.

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  • Mica schists form the prevalent rocks.

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  • It is only found in combination, and is a constituent of the minerals petalite, triphyline, spodumene and lepidolite or lithia mica.

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  • Quincy granite, a hornblende, pyroxene, bluish or greyish, without mica, was used for the construction of the Bunker Hill monument at Charlestown (in 1826), and of King's Chapel, Boston; and for interior decorations it has found some use, for example in the Philadelphia city buildings.

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  • Geologically, the Erzgebirge range consists mainly of gneiss, mica and phyllite.

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  • Among other manufactures are hosiery and knit goods, overalls and suspenders, hardware, lumber, oils and varnishes, gasoline fire engines, mica insulators, agricultural implements, and wagons and carriages.

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  • The gneiss is mostly grey, but occasionally pinkish, its essential constituents (felspar and quartz) being almost always associated with dark mica (biotite) and hornblende in variable quantity.

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  • Such plates are generally made of mica or selenite, and the normal to the plane of polarization of the most retarded stream is called "the axis of the plate."

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  • Below the analyser G a plate H of selenite or mica may be put in the course of the rays.

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  • Built partly on the low ground along the edge of the bay and partly on the hill to the north (a compact mass of mica schist), the city with its white houses enclosed by white walls runs up along natural ravines to the castle of the Heptapyrgion, or Seven Towers, and is rendered picturesque by numerous domes and minarets and the foliage of elms, cypresses and mulberry trees.

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  • Some of these are recognizable as pale yellowish and white mica; others seem to be chlorite, the remainder is perhaps kaolin, but, owing to the minute size of the flakes, they yield very indistinct reactions to polarized light.

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  • It consists of very fine scaly kaolin, larger, shining plates of white mica, grains of quartz and particles of semi-decomposed felspar, tourmaline, zircon and other minerals, which originally formed part of the granite.

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  • The felspar decomposes into kaolin and quartz; its alkalis are for the most part set free and removed in solution, but are partly retained in the white mica which is constantly found in crude china-clays.

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  • physical adsorption was investigated on freshly cleaved mica surfaces.

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  • biotite mica.

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  • cleaved off the mica samples typically obtained from the suppliers.

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  • cleaved off the mica samples typically obtained from the suppliers.

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  • Component parts of a simple variable mica compensator for polarizing microscopes.

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  • Dating deformation using Rb-Sr in white mica; greenschist facies deformation ages from the Entrelor shear zone, Italian Alps.

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  • HOPG (highly orientated pyrolytic graphite) and mica substrates when analyzed by ambient AFM appear to show perfect atomic arrays.

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  • The fresh mica surface provides a highly hydrophilic adsorption substrate.

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  • Physical adsorption was investigated on freshly cleaved mica surfaces.

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  • Micaceous: containing the mineral micaceous: containing the mineral mica, recognizable by the reflections of its single cleavage planes.

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  • Another mineral called mica is ground up to add glitter to lipsticks and nail varnish.

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  • As before stated tin will never be found far from granite, and that granite must have white mica as one of its constituents.

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  • mica based pigment which makes a pearlescent white.

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  • Angular quartz and a variable quantity of white mica up to 0. 1mm across.

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  • white mica is commonly found but quartz is rare.

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  • Their effect can have dazzling and uplifting effects on a home with sparkling mica washes, sunny casein paints and sculptural bas relief work.

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  • mica schist 's, the crystals were moderately good.

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  • mica support substrate.

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  • mica plate like this.

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  • mica sheet under test, hand rotated or tilted in the light path.

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  • mica capacitors.

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  • mica flakes from this area of the rock and study under the microscope.

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  • I have recently obtained, from my contact in the Urals, a large plate of muscovite mica.

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  • Inclusions are dominated by glassy quartz, but sand and silver mica are also usually present.

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  • The darker bands, between 5mm and 10mm thick, are rich in biotite mica.

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  • muscovite mica.

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  • The most common ferromagnesian minerals include olivine, pyroxene, amphibole and mica.

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  • After about 3 miles this gives way to crystalline schist 's, mainly mica and some very black graphite.

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  • We also found some iron pyrites associated with mica schist 's, the crystals were moderately good.

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  • HOPG (highly orientated pyrolytic graphite) and mica substrates when analyzed by ambient AFM appear to show perfect atomic arrays.

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  • Deposits of copper, tin, iron and tungsten have been discovered, and a variety of other mineral products (graphite, mica, spodumene, coal, petroleum, &c.).

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  • A washer of thin flexible mica G concentric with the carbon button is carried by the brass disk, and projecting over the edge of this is held firmly against the rim of the cylindrical wall of the case by an annular brass collar H, which is screwed upon the outer curved surface of this wall.

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  • Some unions annually purchase large quantities ~cono of merchandise for their members, especially chemical mica.

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  • Garnets and mica are everywhere found.

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  • Large beds of mica are found in the east.

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  • In 1870 North Carolina's mica mines were reopened, and they produce the best grade of sheet mica for glazing and a large percentage of the country's yield of this mineral.

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  • portion of the Mountain Region; and that mica was mined here before any European settlement of the country seems proved by numerous excavations and by huge heaps on which are large oak and chestnut trees, some fallen and decayed.

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  • In emery, magnetite in a granular form is largely associated with the corundum; and in certain kinds of mica magnetite occurs as thin dendritic enclosures.

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  • mica, talc, chlorite, haematite), or in long blades or fibres (anthophyllite, tremolite, actinolite, tourmaline), and, when these have a well marked parallel arrangement in definite bands or folia, the rock will break far more easily along the bands than across them.

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  • In the mica-schists of this group biotite or muscovite may be the principal mineral and often both are present in varying proportions; the mica has developed from the argillaceous matter of the original rock; in addition there is always quartz and sometimes felspar (albite or oligoclase).

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  • The phyllites (q.v.) form a middle term between this group and the slates; they consist usually of quartz, white mica and chlorite, and have much of the foliation and schistosity of the mica-schists.

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  • The quartz-schists consist of quartz and white mica, and are intimately related to quartzites.

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  • For the more delicate species, such as the Callithamnia and Ectocarpi, it is an excellent plan to place a small fruiting fragment, carefully floated out in water, on a slip of mica of the size of an ordinary microscopical slide, and allow it to dry.

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  • Many of the freshwater algae which form a mere crust, such as Palmella cruenta, may be placed in a vessel of water, where after a time they float like a scum, the earthy matter settling down to the bottom, and may then be mounted by slipping a piece of mica under them and allowing it to dry.

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  • Ordinary diatoms and desmids may be mounted on mica, as above described, by putting a portion in a vessel of water and exposing it to sunlight, when they rise to the surface, and may be thus removed comparatively free from dirt or impurity.

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  • MICA, a group of widely distributed rock-forming minerals, some of which have important commercial applications.

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  • The name mica is probably derived from the Latin micare, to shine, to glitter; the German word glimmer has the same meaning.

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  • The different species of mica have very nearly the same forms and interfacial angles, and they not infrequently occur intergrown together in parallel position.

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  • When a cleavage flake of mica is struck a sharp blow with a blunt needle-point a six-rayed star of cracks or "percussion figure" is developed: the rays intersect at angles of approximately 60°, and the pair most prominently developed are parallel to the plane of symmetry of the crystal.

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  • A similar six-rayed system of cracks, bisecting the angles between the rays of the previous set, is produced when a blunt punch is gradually pressed against a sheet of mica; this is known as the "pressure figure."

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  • These cracks coincide with planes of easy separation or of gliding in the crystal; they are especially useful in helping to determine the crystallographic orientation of a cleavage flake of mica when crystal faces are absent.

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  • Sheets of mica which have been subjected to earth-movements are frequently cracked and ridged parallel to these directions, and are then valueless for economic purposes.

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  • The acute bisectrix of the optic axes never deviates from the normal to the basal plane by more than a degree or two, hence a cleavage flake of mica will always show an optic figure in convergent light when placed on the stage of a polarizing microscope.

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  • The plane of the optic axes may be either perpendicular or parallel to the plane of symmetry of the crystal, and according to its position two classes of mica are distinguished.

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  • The different kinds of mica vary from perfectly colourless and transparent - as in muscovite - through shades of yellow, green, red and brown to black and opaque - as in lepidomelane; the former have a pearly lustre and the latter a submetallic lustre on the cleavage surfaces.

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  • Sheets of mica very often show coloured rings and bands (Newton's rings), due to the interference of light at the surfaces of internal cleavage cracks.

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  • Inclusions of other minerals are frequently to be observed in mica.

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  • Minute acicular inclusions, probably of rutile, arranged parallel to the rays of the percussion figure, give rise to the phenomenon of "asterism" in some micas, particularly phlogopite: a candle-flame or spot of light viewed through a cleavage sheet of such mica appears as a six-rayed star.

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  • The composition of the several species of mica is given by the following formulae, some of which are only approximate.

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  • Artificially formed crystals of the various species of mica have been observed in furnace-slags and in silicate fusions.

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  • Mica occurs as a primary and essential constituent of igneous rocks of almost all kinds; it is also a common product of alteration of many mineral silicates, both by weathering and by contactand dynamo-metamorphic processes.

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  • The best crystallized specimens of any mica are afforded by the small brilliant crystals of biotite, which encrust cavities in the limestone blocks ejected from Monte Somma, Vesuvius.

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  • These veins consist of felspar, quartz and mica, often with smaller amounts of other crystallized minerals, such as tourmaline, beryl and garnet; they are worked for mica in India, the United States (South Dakota, Colorado and Alabama), and Brazil (Goyaz, Bahia and Minas Geraes).

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  • The principal mining districts are those of Hazaribagh in Bengal and Nellore in Madras; in the former district the mica has usually a ruby tint, whilst in the latter it is more often greenish.

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  • In the Inikurti mine, Nellore, "books" of mica measuring 10 ft.

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  • On account of its transparency and its resistance to fire and sudden changes of temperature, mica has been much used for the windows of stoves and lanterns, for the peep-holes of furnaces, and the chimneys of lamps and gas-burners.

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  • Spangles of mica are much used for decorative purposes of various kinds, and the mineral was formerly known as glacies Mariae (Ger., Frauenglas) because of its use for decorating statues of the Virgin.

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  • The lapis specularis of Pliny, scattered over the Circus Maximus to produce a shining whiteness, was probably mica.

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  • Large quantities of ground mica are used in the manufacture of wall-paper, and to produce a frosted effect on toys, stage scenery, &c. Powdered mica is also used in the manufacture of paints and paper, as a lubricant, and as an absorbent of nitro-glycerine and disinfectants.

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  • Sheets of mica are used as a surface for painting, especially in India; for lantern slides; for carrying photographic films; as a protective covering for pictures and historical documents; for mounting soft and collapsible natural history specimens preserved in spirit; for the vanes of anemometers; mirrors of delicate physical instruments; for various optical and many other purposes.

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  • The most extensive application of mica at the present day is for electrical purposes.

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  • For various purposes a manufactured material known as "micanite" or "micanite cloth" is much used; this consists of small sheets of mica cemented with shellac or other insulating cement on cloth or paper.

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  • Many other uses of mica might be mentioned.

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  • Mica mining is an industry of considerable importance, especially in India; but here the methods of mining are very primitive and wasteful.

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  • In working downwards in open quarries and in tortuous shafts and passages much of the mica is damaged, and a large amount of labour is expended in hauling waste material to the surface.

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  • Since the mineral occurs in definite veins, a more satisfactory and economical method of working would be that adopted in metalliferous mines, with a vertical shaft, cross-cuts, and levels running along the strike of the vein: the mica could then be extracted by overhead stopping, and the waste material used for filling up the worked-out excavations.

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  • In dressing mica the "books" are split along the cleavage into sheets of the required thickness, and the sheets trimmed into rectangles with a sharp knife, shears or guillotine, stained and damaged portions being rejected.

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  • Scrap mica is ground to powder or used in the manufacture of micanite.

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  • The price of mica varies very considerably according to the size, transparency and quality of the sheets.

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  • Holland, "The Mica Deposits of India," Memoirs of the Geological Survey of India (1902), xxxiv.

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  • P. Merrill, The Non-Metallic Minerals (New York, 1904), pp. 163180; "The Mining and Preparation of Mica for Commercial Purposes," Bulletin of the Imperial Institute (London, 1904), ii.

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  • Cirkel, "Mica: its Occurrence, Exploitation and Uses" (Canadian Dept.

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  • of glass or mica.

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  • The slits may be cut out of tin-plate, and half covered by mica or " microscopic glass," held in position by a little cement.

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  • It was used in windows, though by no means exclusively, mica, alabaster and shells having been also employed.

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  • Most of the island is occupied by the band of the old rocks, which include mica, glaucophane and sericite-schists and slates; there are small intrusions of granite, and numerous dikes and masses of basic eruptive rocks.

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  • four series of "Researches on Heat," in the course of which he described the polarization of heat by tourmaline, by transmission through a bundle of thin mica plates inclined to the transmitted ray, and by reflection from the multiplied surfaces of a pile of mica plates placed at the polarizing angle, and also its circular polarization by two internal reflections in rhombs of rock-salt.

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  • Within these limits are to be found most of the minerals known - gold, silver, quicksilver, copper, lead, zinc, iron, manganese, wolfram, bismuth, thorium, vanadium; mica, coal, &c. On or near the coast are coal, salt, sulphur, borax, nitrates and petroleum.

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  • Mica is mined near Mrogoro.

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  • Quincy granite takes a very high polish, owing to the absence of mica and to the coarser cleavage of its hornblende and augite.

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  • Silver follows gold in importance, but the other minerals met with, including gypsum, mica, petroleum, natural gas, granite, marble and tin are not found in paying quantities.

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  • Slates consist largely of thin plates of mica arranged parallel to the cleavage faces.

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  • This mica has developed in the rock as it was folded and compressed.

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  • The faces of slates have usually a slightly silky lustre due to the abundance of minute scales of mica all lying parallel and reflecting light simultaneously from their pearly basal planes.

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  • In microscopic section the best slates show much colourless mica in small, thin, irregular scales.

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  • Green chlorite is usually also abundant in flakes like those of the mica.

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  • The spots contain variety of minerals, sometimes mainly white mica or chlorite.

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  • These crystals may be half an inch to several inches in length; they are usually more or less completely weathered to white mica and kaolin.

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  • In point of absolute mass they are insignificant compared with the abundance and variety of potassiferous silicates, which occur everywhere in the earth's crust; orthoclase (potash felspar) and potash mica may be quoted as prominent examples.

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  • Along with these, similarly, hornblende and diabase occur in the Pelew Islands and gneiss and mica 1 These are dependencies of New Zealand, as are also the following islands and groups which lie apart from the main Polynesian clusters, nearer New Zealand itself: Antipodes Islands, Auckland Islands, Bounty Islands, Campbell Islands, Chatham Islands, Kermadec Islands.

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  • The Concord granite is a medium bluish-grey coloured muscovitebiotite granite, with mica plates so abundant as to effect the durability of the polish of the stone; it is used for building-the outer walls of the Library of Congress at Washington, D.C., are made of this stone-to a less degree for monuments, for which the output of one quarry is used exclusively, and for paving blocks.

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  • granites with an unusually large proportion of soda-lime feldspar), of various grey shades, sometimes tinged with blue, pink or buff, and always marked with black mica; the finer varieties take a high polish and are used for monuments, and the coarser grades are used for construction, especially of railway bridges, and for paving and curbing.

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  • Mica, first mined at grafton|Grafton, Grafton county, in 1803, found also in the northern part of Merrimack county and in the north-western corner of Cheshire county in such quantities that for sixty years:New Hampshire was the largest producer of mica in the United States, is no longer an important product: in 1907 its value ($7227) was less than that of the mica produced in South Dakota, Alabama, North Carolina or Colorado.

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  • Other minerals whose production may be found stated in detail in the annual volume on Mineral Resources of the United States Geological Survey are: natural pigments, felspar, white mica, graphite, fluorspar, arsenic, quartz, barytes, bromine.

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  • - Under the name of Aristotle, three treatises on the good of man have come down to us, Mica Nuco i tkaa (irpos NLKOµaXov, Porphyry), Howe, Eub ipta (7r Os Eiibjµov, Porphyry), and 'HBLKa µeyaXa; so like one another that there seems no tenable hypothesis except that they are the manuscript writings of one man.

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  • The card or "fly," formerly made of cardboard, now consists of a disk either of mica covered with paper or of paper alone, but in all cases the card is divided into points and degrees as shown in fig.

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  • The mica card is generally mounted on a brass framework, F F, with a brass cap, C, fitted with a sapphire centre and carrying four magnetized needles, N, N, N, N, as in fig.

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  • The card is a mica disk, either painted as in fig.

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  • S, Mica card.

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  • Gneiss & Mica Schist A-G.

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  • Just as a granite is a conglomerate or mechanical mixture of distinct crystalline grains of three perfectly definite minerals, mica, quartz, and felspar, so iron and steel in their usual slowly cooled state consist of a mixture of microscopic particles of such definite quasiminerals, diametrically unlike.

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  • The south-western part of the country, a vast and almost level plain, is known as Dar Homr. A granitic sand with abundance of mica and feldspar forms the upper stratum throughout the greater part of Kordofan; but an admixture of clay, which is observable in the north, becomes strongly marked in the south, where there are also stretches of black vegetable mould.

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  • Beneath there appears to be an unbroken surface of mica schist.

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  • The water which has found its way through the granitic sand flows over the surface of the mica schist and settles in the hollows, and by sinking wells to the solid rock a supply of water can generally be obtained.

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  • The other minerals found in the concentrates are pebbles and fragments of pyrope, zircon, cyanite, chrome-diopside, enstatite, a green pyroxene, mica, ilmenite, magnetite, chromite, hornblende, olivine, barytes, calcite and pyrites.

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  • From these rocks in the Ottawa valley are quarried or mined granite, marble, magnificent blue sodalite, felspar, talc, actinolite, mica, apatite, graphite and corundum; the latter mineral, which occurs on a larger scale here than elsewhere, is rapidly replacing emery as an abrasive.

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  • The soil of the Delta is a dark grey fine sandy soil, becoming at times almost a stiff clay by reason of the fineness of its particles, which consist almost wholly of extremely small grains of quartz with a few other minerals, and often numerous flakes of mica.

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  • The Eastern Cordillera is composed of gneiss, mica and chlorite schist and other crystalline rocks of ancient date; the Western Cordillera, on the other hand, is formed of porphyritic eruptive rocks of Mesozoic age, together with sedimentary deposits containing Cretaceous fossils.

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  • Putting aside salt, which has been already treated, the chief mining resources of India at the present day are the coal mines, the gold mines, the petroleum oil-fields, the ruby mines, manganese deposits, mica mines in Bengal, and the tin ores and jade of Burma.

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  • Mica has long been obtained in Bengal, chiefly in the Hazaribagh district, and there is a rubycoloured variety which is held in great estimation.

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  • In Madras also a mica industry has recently grown up. Tin is found in the Tavoy and Mergui districts of Lower Burma, and has for many years been worked in an unprogressive manner chiefly by Chinese labour.

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  • In other cases, Leyden jars or condensers take the form of sheets of mica or micanite or ebonite partly coated with tin foil or silver leaf on both sides; or a pile of sheets of alternate tin foil and mica may be built up, the tin foil sheets having lugs projecting out first on one side and then on the other.

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  • All the lugs on one side are connected together, and so also are all the lugs on the other side, and the two sets of tin foils separated by sheets of mica constitute the two metallic surfaces of the Leyden jar condenser.

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  • It is found in the minerals lepidolite, petalite and in various specimens of mica and of carnallite, and in some mineral waters.

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  • Iron ores are widely distributed, but have not been developed; graphite is mined in Colfax county; mica in Taos county, and to a small extent in Rio Arriba county; marble is quarried in Otero county and sandstone in Bernalillo, Colfax and San Miguel counties.

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  • The rock is a very compact and fine-grained mixture of felspar, quartz and mica, often graduating to mica schist, quartzite and gneiss.

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  • In the western and northern alpine part of Sweden, near the boundaries of Norway, the Silurian strata are covered by crystalline rocks, mica schists, quartzites, &c., of an enormous thickness, which have been brought into their present positions upon a thrust-plane.

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  • In the upper chamber, about half-way between the centre of the base and the apex, was a single skeleton, adorned with beads, copper bracelets and plates of mica; in the lower chamber, directly under the upper and partly in the natural earth, were two skeletons, one adorned with beads and the other without ornament.

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  • The primary rocks which appear at Mitushev Kamen are overlaid with thick beds of quartzites and clayslates containing sulphide of iron, with subordinate layers of talc or mica slate, and thinner beds of fossiliferous limestone, Silurian or Devonian.

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  • The Russian Altai is composed mainly of mica and chlorite schists and slates, together with beds of limestone, and in the higher horizons Devonian and Carboniferous fossils occur in many places.

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  • Mica schists form the prevalent rocks.

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  • It is only found in combination, and is a constituent of the minerals petalite, triphyline, spodumene and lepidolite or lithia mica.

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  • Quincy granite, a hornblende, pyroxene, bluish or greyish, without mica, was used for the construction of the Bunker Hill monument at Charlestown (in 1826), and of King's Chapel, Boston; and for interior decorations it has found some use, for example in the Philadelphia city buildings.

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  • Geologically, the Erzgebirge range consists mainly of gneiss, mica and phyllite.

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  • Among other manufactures are hosiery and knit goods, overalls and suspenders, hardware, lumber, oils and varnishes, gasoline fire engines, mica insulators, agricultural implements, and wagons and carriages.

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  • The gneiss is mostly grey, but occasionally pinkish, its essential constituents (felspar and quartz) being almost always associated with dark mica (biotite) and hornblende in variable quantity.

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  • Such plates are generally made of mica or selenite, and the normal to the plane of polarization of the most retarded stream is called "the axis of the plate."

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  • Below the analyser G a plate H of selenite or mica may be put in the course of the rays.

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  • Built partly on the low ground along the edge of the bay and partly on the hill to the north (a compact mass of mica schist), the city with its white houses enclosed by white walls runs up along natural ravines to the castle of the Heptapyrgion, or Seven Towers, and is rendered picturesque by numerous domes and minarets and the foliage of elms, cypresses and mulberry trees.

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  • high, and the prevailing rocks are granite, mica schist, diorite, porphyry and quartzite, the last, where it crops out on the surface, gleaming in the distance like snow.

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  • Some of these are recognizable as pale yellowish and white mica; others seem to be chlorite, the remainder is perhaps kaolin, but, owing to the minute size of the flakes, they yield very indistinct reactions to polarized light.

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  • It consists of very fine scaly kaolin, larger, shining plates of white mica, grains of quartz and particles of semi-decomposed felspar, tourmaline, zircon and other minerals, which originally formed part of the granite.

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  • The felspar decomposes into kaolin and quartz; its alkalis are for the most part set free and removed in solution, but are partly retained in the white mica which is constantly found in crude china-clays.

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  • After about 3 miles this gives way to crystalline schist 's, mainly mica and some very black graphite.

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  • Natural materials - He used locally-found wood, hand-rubbed metals like copper and natural elements like mica.

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  • Mica Beauty: This line contains no talc, fillers, oils, preservatives, or chemical dyes, and it has a high antioxidant level.

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  • Minerals such as zinc, iron oxides, ultramarine, titanium oxide, bismuth oxychloride and mica are all finely ground into a powder that is gently dusted onto the face with a makeup brush.

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  • Mica: Mica also gives a sparkly effect in this style of makeup.

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  • Mica, the mineral that gives the mineral makeup its silky youthful glow.

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  • The Face Tint does not contain silicones or mica, both ingredients that can cause irritation to sensitive individuals.

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  • Mineral makeup often is made with zinc oxide, titanium dioxide, iron oxide and mica.

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  • These hypoallergenic cosmetics get their pigment from mica, a mineral stone.

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  • Glitter dust or mica: Glitter dust catches and reflects the light making lips appear larger.

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  • True granite is an igneous rock made up of mica, feldspar and quartz.

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  • The quartz, mica and feldspar that make up a granite countertop are ground up and mixed with a pigmented resin.

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  • The circuit board engages the heating element (made out of mica sheets and nichrome wire).

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  • Mica sheets are used as part of the toaster's heating element by providing structure for the Nichrome wire, which is wrapped around the two sheets.

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  • Mica sheets are made out of silicate minerals that can resist heat up to 1600 degrees Fahrenheit.

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  • Nichrome wire is wrapped around the two mica sheets in order to produce rapid heat.

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  • Combined with the mica sheets, the heating element can reach temperatures of up to 1100 to 1200 degrees Fahrenheit.

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  • Chinese Laundry Mica comes in black, red, royal blue and yellow.

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  • Mica powder can be added to soap for sparkle.

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  • Soap Crafters has colorants in powder, liquid, and solid forms, as well as mica.

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  • Brambleberry has colorants of all types, as well as glitter and mica.

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  • KushTush's silk pajamas is more of an off-white, which they call mica, but these are still elegant pajamas in silk charmeuse, and organic is always preferable where available.

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  • Lost Soul was formed in 1989 by Anthony (Tony) Mica and Charles (Charlie) Burke.

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  • Lost Soul was formed in 1989 by Anthony Mica and Charles Burke.

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  • Many of the freshwater algae which form a mere crust, such as Palmella cruenta, may be placed in a vessel of water, where after a time they float like a scum, the earthy matter settling down to the bottom, and may then be mounted by slipping a piece of mica under them and allowing it to dry.

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  • There is considerable difficulty in removing mounted specimens of algae from paper, and therefore a small portion preserved on mica should accompany each specimen, enclosed for safety in a small envelope fastened at one corner of the sheet of paper.

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  • The different kinds of mica vary from perfectly colourless and transparent - as in muscovite - through shades of yellow, green, red and brown to black and opaque - as in lepidomelane; the former have a pearly lustre and the latter a submetallic lustre on the cleavage surfaces.

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  • Sheets of mica very often show coloured rings and bands (Newton's rings), due to the interference of light at the surfaces of internal cleavage cracks.

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  • The composition of the several species of mica is given by the following formulae, some of which are only approximate.

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  • Roscoelite is a mica in which the aluminium is largely replaced by vanadium (V203, 30%); it occurs as brownish-green scaly aggregates, intimately associated with gold in California, Colorado and Western Australia.

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  • Artificially formed crystals of the various species of mica have been observed in furnace-slags and in silicate fusions.

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  • The best crystallized specimens of any mica are afforded by the small brilliant crystals of biotite, which encrust cavities in the limestone blocks ejected from Monte Somma, Vesuvius.

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  • These veins consist of felspar, quartz and mica, often with smaller amounts of other crystallized minerals, such as tourmaline, beryl and garnet; they are worked for mica in India, the United States (South Dakota, Colorado and Alabama), and Brazil (Goyaz, Bahia and Minas Geraes).

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  • The principal mining districts are those of Hazaribagh in Bengal and Nellore in Madras; in the former district the mica has usually a ruby tint, whilst in the latter it is more often greenish.

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  • On account of its transparency and its resistance to fire and sudden changes of temperature, mica has been much used for the windows of stoves and lanterns, for the peep-holes of furnaces, and the chimneys of lamps and gas-burners.

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  • There is considerable difficulty in removing mounted specimens of algae from paper, and therefore a small portion preserved on mica should accompany each specimen, enclosed for safety in a small envelope fastened at one corner of the sheet of paper.

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  • Roscoelite is a mica in which the aluminium is largely replaced by vanadium (V203, 30%); it occurs as brownish-green scaly aggregates, intimately associated with gold in California, Colorado and Western Australia.

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