A Summary of Progress in Petrography. in 1887-1896 |
From inside the book
Results 1-5 of 5
Page 9
... thin section . The fibres are doubly refractive , and have an extinction varying between 13 ° and 38 ° . When heated , the mineral turns green without losing all of its water , and then agrees in most of its properties with copiapite ...
... thin section . The fibres are doubly refractive , and have an extinction varying between 13 ° and 38 ° . When heated , the mineral turns green without losing all of its water , and then agrees in most of its properties with copiapite ...
Page 6
... thin section , and has ∞ Po as the plane of its optical axes , with the acute bisectrix , which is negative . The optical properties of gedrite and pargasite are also investigated . In a few general remarks on the properties of the ...
... thin section , and has ∞ Po as the plane of its optical axes , with the acute bisectrix , which is negative . The optical properties of gedrite and pargasite are also investigated . In a few general remarks on the properties of the ...
Page 8
... thin section they show twinning lamellæ , which disappear when the temperature is raised to 65 ° . The etched ... sections . Freshly precipitated alumina 15 Zeits . f . Kryst . , XIV . , p . 305 . 16 Neues Jahrb . f . Min . etc ...
... thin section they show twinning lamellæ , which disappear when the temperature is raised to 65 ° . The etched ... sections . Freshly precipitated alumina 15 Zeits . f . Kryst . , XIV . , p . 305 . 16 Neues Jahrb . f . Min . etc ...
Page
... thin section are blood red in color . The mineral dissolves with great difficulty in the usual reagents . An analysis gave : SiO2 2.24 ( MgCa ) Co , 2.14 Sb2O 14.18 FeO Mno 22.60 46.97 H2O 9.19 Regarding the silica and carbonate as ...
... thin section are blood red in color . The mineral dissolves with great difficulty in the usual reagents . An analysis gave : SiO2 2.24 ( MgCa ) Co , 2.14 Sb2O 14.18 FeO Mno 22.60 46.97 H2O 9.19 Regarding the silica and carbonate as ...
Page 6
... thin section is pleochroic in yellowish and reddish - yellow tints . It is polysynthetically twinned , and its optical angle 2V = 62 ° 18 ′ . It is , therefore , intermediate in character between olivine and the minerals of the humite ...
... thin section is pleochroic in yellowish and reddish - yellow tints . It is polysynthetically twinned , and its optical angle 2V = 62 ° 18 ′ . It is , therefore , intermediate in character between olivine and the minerals of the humite ...
Other editions - View all
Common terms and phrases
acute bisectrix Al,O Amer AMERICAN NATURALIST amphibole analysis andesites apatite augite axial ratio basalt biotite bisectrix brown Bull calcite Colby University color colorless composition containing cordierite corresponding described diabase diorites double refraction dykes Edited by Dr epidote eruptive Fe,O feldspar FeO CaO MgO FeO MnO Förh formula gabbro garnet Geol gneiss grains granite green ground-mass H₂O hardness hexagonal hornblende inclusions isomorphous Jour Kryst Lacroix lamellæ lithophysæ lustre magma magnetite MAKERS SYRACUSE manganese mica microlites mineral occurs MINERALOGY AND PETROGRAPHY.¹ molecule monoclinic Na,O Na₂O nepheline Neues Jahrb olivine optical angle optical axes original orthoclase orthorhombic Petrog PETROGRAPHY.¹ Petrographical phenocrysts plagioclase pleochroic porphyritic porphyritic crystals pressure prismatic produced pyroxene quartz regarded resembles rhombohedral rocks scapolite schists silica small crystals specific gravity spherulites structure substance symmetry thin section tion twinning plane variety W. S. Bayley Waterville yellow yielded Zeits
Popular passages
Page 5 - The olivine is surrounded by a reactionary rim consisting of an inner zone of hypersthene and an outer one of actinolite.