A Summary of Progress in Petrography. in 1887-1896 |
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Page 8
... crystals of a clear yellow color , that become colorless in thin section . The other variety is light orange , becoming golden yellow in the section . Both possess the same optical properties , except that the orange crystals are ...
... crystals of a clear yellow color , that become colorless in thin section . The other variety is light orange , becoming golden yellow in the section . Both possess the same optical properties , except that the orange crystals are ...
Page 9
... crystals of bright red andalu- site , and also black tourmaline , sphene , muscovite , and garnet dissemi- nated in a ground - mass of feldspar and quartz . Other granulites are very rich in cordierite , and these are in general less ...
... crystals of bright red andalu- site , and also black tourmaline , sphene , muscovite , and garnet dissemi- nated in a ground - mass of feldspar and quartz . Other granulites are very rich in cordierite , and these are in general less ...
Page 10
... crystals , without well - developed faces . According to Darapsky their streak is orange , hardness 3 , and density 2.18 . They are but slightly soluble in water or in cold hydrochloric acid , but easily dissolve in hot acid . Their ...
... crystals , without well - developed faces . According to Darapsky their streak is orange , hardness 3 , and density 2.18 . They are but slightly soluble in water or in cold hydrochloric acid , but easily dissolve in hot acid . Their ...
Page 11
... crystals . It was found by Flink in granular dolomite at Langbanshyttan , associated with haus- mannite . The density of the new mineral is 3.881 , and its hardness is 6. It is soluble in strong hydrochloric acid with evolution of ...
... crystals . It was found by Flink in granular dolomite at Langbanshyttan , associated with haus- mannite . The density of the new mineral is 3.881 , and its hardness is 6. It is soluble in strong hydrochloric acid with evolution of ...
Page 12
... crystals in terms of the hexagonal sys- tem with a c = 1 : .7233 . They are thick , tabular forms , bounded by oP , ∞P2 , ∞P , § P2 , P2 and 15 P , and other pyramids with com- plicated symbols . Brögger finds that sections parallel ...
... crystals in terms of the hexagonal sys- tem with a c = 1 : .7233 . They are thick , tabular forms , bounded by oP , ∞P2 , ∞P , § P2 , P2 and 15 P , and other pyramids with com- plicated symbols . Brögger finds that sections parallel ...
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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...