A Summary of Progress in Petrography. in 1887-1896 |
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Page 8
... 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 pleochroic in pale yellow and ...
... 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 pleochroic in pale yellow and ...
Page 14
... color and a metallic lustre , has a density of 2.31 , and a com- position as follows : SO , Fe2O , Na2O H2O 42.93 22.86 17.49 15.66 = 2Na2SO1 + Fe , S , O , + 6H2O The mineral is from Sierra Gorda , near Caracoles . It is identical with ...
... color and a metallic lustre , has a density of 2.31 , and a com- position as follows : SO , Fe2O , Na2O H2O 42.93 22.86 17.49 15.66 = 2Na2SO1 + Fe , S , O , + 6H2O The mineral is from Sierra Gorda , near Caracoles . It is identical with ...
Page 15
... color parallel to the longer axis , and no color at right angles to this . The formula ascribed to the substance differs from Frenzel's formula in lacking one molecule of water . Ferronatrite , although obtainable only in white or ...
... color parallel to the longer axis , and no color at right angles to this . The formula ascribed to the substance differs from Frenzel's formula in lacking one molecule of water . Ferronatrite , although obtainable only in white or ...
Page 16
... color from violet to orange red , and united into parallel aggregates . Their axial ratio is a : b : c = 1.9192 : 1 : .5245 with ẞ = 84 ° 1 ′ , on the assumption of the plane P , determined by Descloizeaux in the Limoges crystals as the ...
... color from violet to orange red , and united into parallel aggregates . Their axial ratio is a : b : c = 1.9192 : 1 : .5245 with ẞ = 84 ° 1 ′ , on the assumption of the plane P , determined by Descloizeaux in the Limoges crystals as the ...
Page 17
... color and a brilliant lustre , inclining to pearly on the perfect cleavage . Its composition agrees with the symbol Ca , Mn ( PO ) , + 2H , O . Dickin- sonite is a bright green chlorite - like mineral with a micaceous struc- ture and ...
... color and a brilliant lustre , inclining to pearly on the perfect cleavage . Its composition agrees with the symbol Ca , Mn ( PO ) , + 2H , O . Dickin- sonite is a bright green chlorite - like mineral with a micaceous struc- ture 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...