Aluminium, test for, by Borichy’s method, 137 test for, by Behren’s method, 139 Amorphous bodies, 2 Amorphous substances, test for, 26 ▄Amphibole▄, 84 ▄Analcite▄, 56 Analyzer, 10 ▄Andalusite▄, 72 Anhedron, 15 Anisotropic character, test for, 27 Anisotropic crystals, 2 Anomalies, optical, 27 ▄Anorthite▄, 103 ▄Anorthoclase▄, 113 ▄Anthophyllite▄, 88 ▄Antigorite▄, 114 ▄Apatite▄, 68 Apatite, recognition of, by test for phosphorus, 139 Apparatus for petrographical laboratory, 127 Appendix, 141 ▄Arfvedsonite▄, 88 ▄Augite▄, 80 Automorphic, 13 Axes of elasticity, 4 Axial angle, 5 determination of, 47 Axial plane, 5 ▄Basaltic Hornblende▄, 85 ▄Bastite▄, 77 Becke’s method for determining relative values of refractive indices, 19 Behren’s method. (Hydrofluoric and sulphuric acids), 137 Bertrand lens, 11 Biaxial crystals, 4, 5 vibration directions in, 4 Biaxial interference figures, 43 ▄Biotite▄, 89 Bisectrix, acute, 5 obtuse, 5 Borichy’s method. (Hydrofluosilicic acid), 135 Broken or strained crystals, 15 ▄Bronzite▄, 76 ▄Calcite▄, 65 Calcium, test for, by Borichy’s method, 136 test for, by Behren’s method, 138 “Cap” nicol, 10 ▄Carbonaceous Matter▄, 61 Carbonaceous particles, test for, 132 Carbonates, test for, 130 Cement, 122 for mounting, 126 Cementing, 121 Centering stage, 10 ▄Chalcedony▄, 64 Characters observed by, convergent light, 40 crossed nicols, 26 reflected light, 13 polarized light, 25 Characters of opaque minerals, 13 transparent minerals, 13 Chemical and mechanical tests, 129 Chemical (micro) reactions, 134 separation, 134 tests on crystal in section, 129 ▄Chiastolite▄, 72 ▄Chlorite group▄, 92 ▄Chromite▄, 52 ▄Chrysolite▄, 77 ▄Chrysotile▄, 114 Circular polarization, 3 Classification into systems by optical determinations, 141 ▄Clay▄, 115 Cleaning and finishing sections, 126 Cleaning microscope, 11 Cleavage, 23 ▄Clinozoisite▄, 96 Color, 17 diagram (interference), 143 fringes, 48 Condensing lens, 9 Consolidation of minerals in plutonic rocks, order of, 144 Conventions, ix Convergent light, 40 characters observed by, 40 Convergent and parallel light, résumé of uses of, 49 ▄Cordierite▄, 78 Corroded crystals, 15 ▄Corundum▄, 62 Crossed nicols, characters observed by, 26 Crossed twinning, 37 Crystallites, 16 Crystallizations obtained by Behren’s method, 137 Borichy’s method, 135 Crystals bounded by planes, 13 Crystals without bounding planes, 15 Cutting, 120 Cutting and grinding machines, 117 ▄Cyanite▄, 113 ▄Damourite▄, 92 ▄Delessite▄, 94 Diagram, showing relation between strength of double refraction, interference colors and thickness of section, 143 ▄Diallage▄, 80 Diamond saws, 119 ▄Dichroite▄, 78 ▄Diopside▄, 80 ▄Dipyre▄, 59 Directions of elasticity, ix Dispersion, 5, 48 ▄Disthene▄, 113 ▄Dolomite▄, 67