A Summary of Progress in Petrography. in 1887-1896 |
From inside the book
Results 1-5 of 8
Page 9
... imbedded in the amphiboloids . Some of the granulites contain corroded 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 ...
... imbedded in the amphiboloids . Some of the granulites contain corroded 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 ...
Page 17
... imbedded in byssolite , thuringite , and calcite in pockets in a magnetic iron ore . The principal type of the chalcopyrite is the sphenoid often modified by a scalenohedron . All the faces are striated , and frequently they are so much ...
... imbedded in byssolite , thuringite , and calcite in pockets in a magnetic iron ore . The principal type of the chalcopyrite is the sphenoid often modified by a scalenohedron . All the faces are striated , and frequently they are so much ...
Page 19
... imbedded in the form of small , colorless , transparent , or milky - white crystals in the pinnolite of Stassfurt , Germany . The crystals are monoclinic , with two perfect cleavages perpendicular to the plane of symmetry . of these is ...
... imbedded in the form of small , colorless , transparent , or milky - white crystals in the pinnolite of Stassfurt , Germany . The crystals are monoclinic , with two perfect cleavages perpendicular to the plane of symmetry . of these is ...
Page
... imbedded in colorless calcite as brilliant iron - black skeleton dodecahedrons , elongated in the direction of one of the crystallographic or one of the octahedral axes . The mineral is sectile . It possesses no cleavage , has a ...
... imbedded in colorless calcite as brilliant iron - black skeleton dodecahedrons , elongated in the direction of one of the crystallographic or one of the octahedral axes . The mineral is sectile . It possesses no cleavage , has a ...
Page
... imbedded in clay , yielded Genth : " Bi = 77-54 ; S = 14.06 ; Se S.So , corresponding to 4B1 ̧§ , + Bi̟Se̟ ̧ . It probably came from Guadalajara , Mex . density is 6.306 . As the mineral was sent to the author as a specimen of ...
... imbedded in clay , yielded Genth : " Bi = 77-54 ; S = 14.06 ; Se S.So , corresponding to 4B1 ̧§ , + Bi̟Se̟ ̧ . It probably came from Guadalajara , Mex . density is 6.306 . As the mineral was sent to the author as a specimen of ...
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...