A Summary of Progress in Petrography. in 1887-1896 |
From inside the book
Results 1-5 of 15
Page 9
... produced in them are analogous to those produced by the basalts . Much new feldspar has been generated in them , and this is usually optically continuous with the original feld- spar to which it is attached . Tridymite is also an ...
... produced in them are analogous to those produced by the basalts . Much new feldspar has been generated in them , and this is usually optically continuous with the original feld- spar to which it is attached . Tridymite is also an ...
Page 10
... produced in the inclusion ; whereas in the case of the basaltic altera- tion the last two are found in the metamorphosed rock . In a later article Lacroix 3 summarizes the results of his study of inclusions , with reference especially ...
... produced in the inclusion ; whereas in the case of the basaltic altera- tion the last two are found in the metamorphosed rock . In a later article Lacroix 3 summarizes the results of his study of inclusions , with reference especially ...
Page 12
... produce an apparently hexagonal form . The axial ratio on the assumption of triclinic symmetry becomes a : b : c ... produced by Gramont in the wet way . One part of borax and two of magnesium chloride were moistened with water and ...
... produce an apparently hexagonal form . The axial ratio on the assumption of triclinic symmetry becomes a : b : c ... produced by Gramont in the wet way . One part of borax and two of magnesium chloride were moistened with water and ...
Page 13
... produced little prismatic crystals of a substance differing from nosean in the addition of two molecules of water . 13 Physical Mineralogy . - The discussion as to the cause of optical anomalies in uniaxial crystals has received another ...
... produced little prismatic crystals of a substance differing from nosean in the addition of two molecules of water . 13 Physical Mineralogy . - The discussion as to the cause of optical anomalies in uniaxial crystals has received another ...
Page 14
... produced . The symmetry of the figures obtained indicate a tetragonal symmetry for the mineral . Anomalous figures on some crystals , found only on planes that show double refraction , are explained as due to the manner of growth . Many ...
... produced . The symmetry of the figures obtained indicate a tetragonal symmetry for the mineral . Anomalous figures on some crystals , found only on planes that show double refraction , are explained as due to the manner of growth . Many ...
Other editions - View all
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...