Bulletin, Ausgabe 708U.S. Government Printing Office, 1922 |
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_do____ 50 feet abundant Air shrinkage ball clay beds borings burned clay cent in terms cent__ clay from pit cone contains County Creek crucibles crude clay depth diaspore dike Dillsboro domestic clays dry clay east English clay feet thick feldspar Ferric oxide Fire tests flakes flint clay formation Geological Georgia grades grains high-grade hydromica inch__ indianaite kaolinite Lagrange lignite limonite Linear manufacture material mica microscope miles mineral Mitchell County mixture Modulus of rupture Mount Holly Springs occur outcrop overburden pegmatite physical tests porcelain body Porosity Porosity per cent pounds per square quantity quartz residual clay rock rutile sample sand sandstone sandy Saylorsburg schist shaft shows shrinkage per cent sieve sieve__ Silica South Carolina Sprucepine square inch stained Steel hard streaks Temperature Tenn Tennessee terms of dry terms of volume tests of clay tons tourmaline tunnel Volume shrinkage wall washed clay Water of plasticity white clay zircon
Beliebte Passagen
Seite 194 - REPORT ON THE CLAY DEPOSITS of Woodbridge, South Amboy and other places in New Jersey, together with their uses for firebrick, pottery, &c.
Seite 23 - Their thickness ranges from a fraction of an inch up to 6 or more feet. Many of them are lenticular in shape, the length varying from four or five to twenty or more times the thickness. ' In numerous places these quartz streaks or veins are persistent through the whole length of the pegmatite exposed. Some inclose feldspar or mica bodies; others do not. The quartz of these segregations is massive and generally granular, though locally crystallized. If crystallized it may be translucent or clear and...
Seite 57 - He states that tunnels and shafts had been dug over an area one-half mile long and one-eighth mile wide, and that "at one point a considerable quantity of fine white kaolin is encountered. There are, however, occasional streaks of fresh feldspar and on all sides of the lens there is semi-kaolinized material; these facts justify the assumption that the kaolin is merely an isolated lens and would not justify the equipment of an extensive outfit for handling it, although the presence in the neighborhood...
Seite 23 - The mica occupies various positions in the pegmatite. Where the rock has a typical granitic texture, the mica may be found evenly distributed through it. More commonly the larger crystals will be found either in clusters at intervals through the "vein," in places connected by streaks of small crystals, or collected along one or both walls of the pegmatite, with some of the crystals partly embedded in the wall rock. Where there is a quartz streak within the pegmatite, the mica occurs on either or...
Seite 22 - Pegmatite is closely allied to granite in composition. As in granite, the essential constituents are feldspar and quartz, with more or less mica and other accessory minerals. Though hornblende is rather a common mineral in granite, it is less so in pegmatite. Orthoclase and microcline are the most common varieties of feldspar found in pegmatite. In many places, however, a variety of plagioclase, either albite or oligoclase, makes up part or all of the feldspar component.
Seite 65 - The property is undeveloped, but cuts on the railway and on the highway one-fourth mile west of the railroad expose a white kaolin. On the east side of the railroad right-of-way a section of about 160 feet is exposed and between this and the track are a couple of shallow pits. The section is in alternating schists and kaolin. At its north end a width of 20 feet of kaolin is shown, followed to the south by 20 feet of quartz, 110 feet of kaolin and finally schists. (See Fig.
Seite 44 - ... referred to above as having been explored by borings that cover about four and two-thirds acres. The borings are in lines running northeast and northwest and at intervals of about 50 feet. The overburden averages in thickness not more than seven or eight feet and the depth of the clay penetrated varies from 20 to 45 feet. On the assumption that the average thickness of the clay is 30 feet and that the average yield of commercial kaolin is about 20 per cent of the crude tonnage the productive...
Seite 18 - ... belts of kaolin that result from the decomposition of pegmatite dikes. Where feldspathic granites or other feldspathic rocks occur over large areas these may give rise to deposits of kaolin (the "blanket deposits" of Ries) that are so large, that by their very massiveness they may reveal themselves on the surface. Because of its striking appearance, the kaolin, even when much mixed with other materials, may be recognized, and, because it may migrate down slopes, in many cases it may appear to...
Seite 141 - ... small white granules of clay, producing an amygdaloidal structure. These small granules have about the same degree of hardness as the surrounding kaolin. Under the microscope the porcelain-like kaolin exhibits a granular appearance, the grains being apparently spherical in form and in some sections arranged in a dendritic structure. The dendritic structure may be due to the loss of water and consequent shrinkage when the section is heated during its preparation. In some places the white kaolin...
Seite 22 - Horses, or inclusions of wall rock, are common in pegmatite. Some of them are in the form of bands or sheets parallel to the walls, and the schistosity of these bands is also parallel to the walls. They range from an inch or two up to several feet in thickness, and their length may be many times their width. Elsewhere they occur as irregularly shaped masses, from a few inches up to several feet thick.