A Summary of Progress in Petrography. in 1887-1896 |
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Page 1888
... axial ratio 1.2594 : 1 : .6018 , and the plane of its optical axes parallel to ∞ Poo . From the few chemical tests made upon the small amount of material at his command , Fletcher supposes the mineral to be an oxychloride of lead ...
... axial ratio 1.2594 : 1 : .6018 , and the plane of its optical axes parallel to ∞ Poo . From the few chemical tests made upon the small amount of material at his command , Fletcher supposes the mineral to be an oxychloride of lead ...
Page 1889
... optical axes is oP , and the optical angle 2 V is about 90 ° , with b as the positive acute bisectrix . The pleochroism is weak in yellow tints . The mineral is infusible before the blowpipe , and has a specific gravity of 3.24-3.31 ...
... optical axes is oP , and the optical angle 2 V is about 90 ° , with b as the positive acute bisectrix . The pleochroism is weak in yellow tints . The mineral is infusible before the blowpipe , and has a specific gravity of 3.24-3.31 ...
Page 1896
... axial ratio 1.2594 : 1 : .6018 , and the plane of its optical axes parallel to P. From the few chemical tests made upon the small amount of material at his command , Fletcher supposes the mineral to be an oxychloride of lead ...
... axial ratio 1.2594 : 1 : .6018 , and the plane of its optical axes parallel to P. From the few chemical tests made upon the small amount of material at his command , Fletcher supposes the mineral to be an oxychloride of lead ...
Page 1897
... optical axes is oP , and the optical angle 2V is about 90 ° , with b as the positive acute bisectrix . The pleochroism is weak in yellow tints . The mineral is infusible before the blowpipe , and has a specific gravity of 3.24-3.31 . It ...
... optical axes is oP , and the optical angle 2V is about 90 ° , with b as the positive acute bisectrix . The pleochroism is weak in yellow tints . The mineral is infusible before the blowpipe , and has a specific gravity of 3.24-3.31 . It ...
Page 1898
... optical axes is perpendicular to ∞ Poo , and the value of the optical angle is nearly 90 ° The principal bisectrix probably coincides with the axis b . Specific gravity = 4.39 . — Messelite is found in aggregates of colorless or brown ...
... optical axes is perpendicular to ∞ Poo , and the value of the optical angle is nearly 90 ° The principal bisectrix probably coincides with the axis b . Specific gravity = 4.39 . — Messelite is found in aggregates of colorless or brown ...
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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.