A Summary of Progress in Petrography. in 1887-1896 |
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Page 9
... feldspar and quartz . Other granulites are very rich in cordierite , and these are in general less rich in quartz than are those bearing andalusite . Micaceous and quartzitic schists from the neighborhood of Ax embrace zircon , apatite ...
... feldspar and quartz . Other granulites are very rich in cordierite , and these are in general less rich in quartz than are those bearing andalusite . Micaceous and quartzitic schists from the neighborhood of Ax embrace zircon , apatite ...
Page 13
... feldspar - like silicate , combined with meta- or orthosilicic acid , and also an amount of water varying with the temperature . The crystal water may be driven off at high temperature , and taken up again at a lower one , and the ...
... feldspar - like silicate , combined with meta- or orthosilicic acid , and also an amount of water varying with the temperature . The crystal water may be driven off at high temperature , and taken up again at a lower one , and the ...
Page 14
... feldspar , quartz , mica , and hornblende . There are present in it also garnet , zircon , magnetite , augite , and sillimanite , and with them is mixed a nitrogenous organic substance . The most interesting con- stituents of the dust ...
... feldspar , quartz , mica , and hornblende . There are present in it also garnet , zircon , magnetite , augite , and sillimanite , and with them is mixed a nitrogenous organic substance . The most interesting con- stituents of the dust ...
Page 14
... feldspar , amphi- bolites and mica - schists , each of which classes is briefly described . The segregations mentioned occur most frequently near the contact of the granite with the schists . Many of them resemble so closely certain ...
... feldspar , amphi- bolites and mica - schists , each of which classes is briefly described . The segregations mentioned occur most frequently near the contact of the granite with the schists . Many of them resemble so closely certain ...
Page 14
... feldspar is albite . Gabbros and peridotites cut the Paleozoic strata . In some specimens of the former piedmontite was noticed as an alteration product of hornblende . the Mesozoic occurs the largest quantity of eruptives . Granite and ...
... feldspar is albite . Gabbros and peridotites cut the Paleozoic strata . In some specimens of the former piedmontite was noticed as an alteration product of hornblende . the Mesozoic occurs the largest quantity of eruptives . Granite and ...
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Common terms and phrases
acid Al,O alteration Amer AMERICAN NATURALIST analysis andalusite angle aragonite augite axial ratio basalts beryl biotite brucite Bull calcite calcium chlorite cleavage Colby University color colorless composition constituents containing cordierite corresponding crystalline crystals density described diabase double refraction dyke eruptive rocks Fe,O Fe₂O feldspar FeO MgO CaO FeO MnO forms formula Franc gabbro-diorites gabbros garnet Genth gneisses granite granulites ground-mass H₂O habit hexagonal hornblende humite hypersthene imbedded inclusions Jour Kryst leucite masses melanophlogite metacinnabarite mica mineral MINERALOGY AND PETROGRAPHY.¹ Mitth molecules muscovite Neues Jahrb nosean occur olivine optical original orthoclase ottrelite parallel Penfield Petrog PETROGRAPHY.¹ Petrographical phenacite plagioclase plane plates polymorphism prismatic produced pseudomorphs pyroxene quartz regarded rock individual Rosenbusch schistose schists serpentine silica sodium soluble specific gravity specimens spinel structure substance sulphur symmetry tabular temperature tonalite tourmaline twinned varieties W. S. Bayley Waterville yielded Zeits zircon zone
Popular passages
Page 19 - The plane of the optical axes is perpendicular to the plane of symmetry, and makes with c an angle of °7 in acute /9. A = b. 2H na = 104° 27'.
Page 14 - The larger part of the dust is thought to be a sediment from the air, and to have been obtained by it from a region of crystalline schists. The chondri, on the other hand, are thought to be of cosmic origin, since they are similar to the chondri obtained in deep-sea soundings. If the amount of the dust collected from the snow in Greenland represents the fall of one year, the total amount falling upon the entire surface of the earth in this time is 125 million kilograms, equivalent to a cube of thirty-one...
Page 14 - Wiilfing 21 for investigation, by whom it has been found to consist in greater part of feldspar, quartz, mica, and hornblende. There are present in it also garnet, zircon, magnetite, augite, and sillimanite, and with them is mixed a nitrogenous organic substance. The most interesting constituents of the dust...