A Summary of Progress in Petrography. in 1887-1896 |
From inside the book
Results 1-5 of 23
Page 1888
... hardness 5-5.5 . It is soluble in hydrochloric acid , decrepitates when heated , and breaks into an infusible and insoluble powder . Its com- position is : 2 3 SiO , PbO Tho , MnO FeO CaO Al , O , Ce , O , Y2O , ( LaDi ) , 0 , 29.17.854 ...
... hardness 5-5.5 . It is soluble in hydrochloric acid , decrepitates when heated , and breaks into an infusible and insoluble powder . Its com- position is : 2 3 SiO , PbO Tho , MnO FeO CaO Al , O , Ce , O , Y2O , ( LaDi ) , 0 , 29.17.854 ...
Page 1889
... hardness of 4.5 , and Sp . Gr = 3.87 . Its composition is : 29. I 2.5 1.7 9.9 The As2O , Sb , O , Mn , O , Fe , O , MnO CaO MgO HO 20.2 1.5 35.8 .4 -Fouquéite . — In his excellent paper on scapolite rocks , Lacroix 15 describes a ...
... hardness of 4.5 , and Sp . Gr = 3.87 . Its composition is : 29. I 2.5 1.7 9.9 The As2O , Sb , O , Mn , O , Fe , O , MnO CaO MgO HO 20.2 1.5 35.8 .4 -Fouquéite . — In his excellent paper on scapolite rocks , Lacroix 15 describes a ...
Page 1896
... hardness 5-5.5 . It is soluble in hydrochloric acid , decrepitates when heated , and breaks into an infusible and insoluble powder . Its com- position is : 2 Sio , PbO Tho , MnO FeO CaO AIO , Ce2O , Y2O , ( LaDi ) , O ̧ 29.17.854 12.00 ...
... hardness 5-5.5 . It is soluble in hydrochloric acid , decrepitates when heated , and breaks into an infusible and insoluble powder . Its com- position is : 2 Sio , PbO Tho , MnO FeO CaO AIO , Ce2O , Y2O , ( LaDi ) , O ̧ 29.17.854 12.00 ...
Page 1897
... hardness of 4.5 , and Sp . Gr = 3.87 . Its composition is : As2O Sb , Mn , O , Fe2O , MnO CaO MgO HO 20.2 1.5 35.8 .4 29. I 1.7 9.9 The 2.5 -Fouquéite . In his excellent paper on scapolite rocks , Lacroix 15 describes a dimorphous form ...
... hardness of 4.5 , and Sp . Gr = 3.87 . Its composition is : As2O Sb , Mn , O , Fe2O , MnO CaO MgO HO 20.2 1.5 35.8 .4 29. I 1.7 9.9 The 2.5 -Fouquéite . In his excellent paper on scapolite rocks , Lacroix 15 describes a dimorphous form ...
Page 1898
... hardness of 5-6 . It is biaxial , with an optical angle ( in air ) of about 100 ° . Its analysis shows it to be a bi- silicate with the composition : 2 SiO , MnO 51.6 3.4 CaO MgO Al , O ,. FeO ̧ 23.3 13.5 1.4 KO . Na2O 6.8 -Michel ...
... hardness of 5-6 . It is biaxial , with an optical angle ( in air ) of about 100 ° . Its analysis shows it to be a bi- silicate with the composition : 2 SiO , MnO 51.6 3.4 CaO MgO Al , O ,. FeO ̧ 23.3 13.5 1.4 KO . Na2O 6.8 -Michel ...
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.