Introduction to Mineralogy

WILLIAM D. NESSE University of Northern Colorado

New York • Oxford OXFORD UNIVERSITY PRESS 2000 Contents

Preface xiii Crystal Forms 24 Isometric Forms 24 Nonisometric Forms 25 PARTI: CRYSTALLOGRAPHY Combining Crystal Forms 28 Enantiomorphous Forms and Crystals 28 AND CRYSTAL CHEMISTRY Positive and Negative Forms 29 Forms in the Six Crystal Systems 29 Chapter 1: Introduction 3 Triclinic Crystal System 29 Monoclinic Crystal System 30 Minerals 3 Orthorhombic Crystal System 30 Mineraloids 4 Tetragonal Crystal System 31 Mineralogy 4 Hexagonal Crystal System 31 Mineral Names 4 Isometric Crystal System 33 General References on Mineralogy 5 Crystal Habit 34 References Cited and Suggestions for Additional References Cited and Suggestions for Additional Reading 5 Reading 38

Chapter 2: Crystallography 6 Chapter 3: Crystal Chemistry 39 Introduction 6 Introduction 39 Translational Symmetry 6 The Nature\of Chemical Elements 39 Plane Lattices 6 Nucleus 39 Space Lattices and Unit Cell 7 Electrons 39 Bravais Lattices and Crystal Systems 8 Formation of Ions 41 Point Symmetry 12 Abundance of the Elements 45 Reflection 12 Chemical Bonding 46 Rotation 12 Valence-Related Bonding 46 Inversion 12 Relation among the Valence-Dependent Compound Symmetry Operations 12 Bonds 51 Symmetry Notation 13 Bonds Not Involving Valence Electrons 52 32 Point Groups 14 Size of Atoms and Ions 53 Steno's/.ow 15 Oxidation State 54 Measurement of Crystal Angles 17 Coordination 55 Determining Crystal System and Crystal References Cited and Suggestions for Additional Class 1 7 Reading 56 Space Groups 17 Crystal Faces 19 Laws of Hauy and Bravais 19 Chapter 4: Crystal Structure 57 M/7/er Indices 19 Introduction 57 Indices and Crystal Axes in the Hexagonal Crystal Controls of Crystal Structure 57 System 20 Structure Controls with Metallic Bonding 57 Determining Miller Index 22 Structure Controls with Covalent Bonding 58 Assigning Miller Indexes by Inspection 23 Structure Controls with Molecular l Crystallographic Directions 23 Crystals 58 Zones 23 Structure Controls with Ionic Bonding 59 vii viii • Contents

Application of Pauling's Rules 64 Specific Gravity 97 Illustrating Mineral Structures 65 Properties Related to Mechanical Cohesion 99 Isostructural Minerals 65 Hardness 99 Polymorphism 66 Tenacity 100 Reconstructive Polymorphism 67 Cleavage 100 Displacive Polymorphism 68 Fracture 101 Order-Disorder Polymorphism 68 Parting 101 Polytypism 69 Color and Luster 102 Mineral Classification 69 Light 102 Compositional Variation in Minerals 69 Perception of Color 102 Substitutional Solid Solution 70 Mineral Luster 103 Mineral Formulas 71 Mineral Color 103 Graphic Representation 72 Color from Mechanical Causes 106 Binary Diagrams 72 Consistency of Mineral Color 107 Ternary Diagrams 72 Streak 107 References Cited and Suggestions for Additional Luminescence 107 Reading 73 Magnetism 108 Diamagnetism 108 Chapter 5: Crystal Growth 74 Paramagnetism 108 Introduction 74 Ferromagnetism 110 Mineral Stability 74 Ferrimagnetism 110 Stability 74 Electrical Properties 110 Cibbs Free Energy 75 Electrical Conductivity 110 Mineral Reactions 75 Piezoelectricity 111 Mineral Nucleation 77 Pyroelectricity 112 Homogeneous Nucleation 77 Miscellaneous Properties 112 Heterogeneous Nucleation 79 References Cited and Suggestions for Additional Crystal Growth 79 Reading 113 Rate of Growth 80 Zoned Crystals 81 Chapter 7: Optical Mineralogy 114 Structural Defects 84 Introduction 114 Point Defects 84 Light 114 Line Defects 84 Lightwaves 114 Planar Defects 86 Twinning 87 Polarized Light 115 Postcrystallization Processes 90 Interaction of Light and Matter 116 Ordering 90 Optically Isotropic versus Anisotropic Twinning 90 Materials 116 Recrystallization 91 Reflection and Refraction 117 Exsolution 91 Dispersion 118 Pseudomorphism 92 Petrographic Microscope 118 Radioactivity and Minerals 93 Illuminator 118 References Cited and Suggestions for Additional Substage Assembly 118 Reading 94 Microscope Stage 119 Objective Lenses 119 Upper Polarizer 120 PART II: MINERAL PROPERTIES, Bertrand Lens 120 STUDY, AND IDENTIFICATION Oculars 120 Focusing Mechanism 121 Accessories 121 Chapter 6: Physical Properties of Direction Conventions 121 Minerals 97 Isotropic Materials 121 ; Introduction 97 Anisotropic Minerals 122 Mass-Dependent Properties 97 Interference Phenomena 122 , . Density 97 Use of the Interference Color Chart 126 Contents ix

Extinction 127 References Cited and Suggestions for Additional Function of Accessory Plates 127 Reading 168 Optical Indicatrix 130 Isotropic Indicatrix 130 Chapter 9: Chemical Analysis of Uniaxial Indicatrix 131 Minerals 169 Biaxial Indicatrix 133 Introduction 169 Mineral Color and Pleochroism 136 Analytical Methods 169 Isotropic Minerals 136 Wet Chemical 169 Uniaxial Minerals 136 Electron Probe Microanalysis 169 Biaxial Minerals 137 X-Ray Fluorescence 170 Extinction Angle and Sign of Elongation 137 Mass Spectrometry 171 Extinction Angle 137 Conventions in Reporting Chemical Sign of Elongation 138 Analyses 171 Categories of Extinction 138 Conversion of Chemical Analyses to Structural Extinction in Uniaxial Minerals 139 Formulas 172 Extinction in Biaxial Minerals 139 References Cited and Suggestions for Additional Interference Figures 139 Reading 174 Uniaxial Interference Figures 140 Biaxial Interference Figure 143 Chapter 10: Strategies for Study 175 Refractometry: Measurement of Index of Refraction 151 Introduction 175 Immersion Method 151 Mineral Identification Tactics 175 Refractometry in Thin Section 155 Mineral Separation 175 Isotropic Minerals 156 Hand Sample Identification 177 Uniaxial Minerals 156 Thin Section Identification 178 Biaxial Minerals 156 Grain Mount Identification 179 Reflected Light Optics 156 Polished Section Identification 1 79 Observation in Plane Polarized Light 157 X-Ray Diffraction 179 Observations with Crossed Polarizers 157 Mineral Association 179 Tactics for Mineral Identification 157 Problems \n Paradise 180 Thin Section Identification 158 References Cited and Suggestions for Additional Grain Mount Identification 158 Reading 180 Polished Section Identification 159 References Cited and Suggestions for Additional Reading 159 PART III: MINERAL DESCRIPTIONS

Chapter 8: Introduction to X-Ray Chapter 11: Silicates 183 Crystallography 160 Introduction 183 Introduction 160 Silicate Structure and Classification 183 X-Rays 160 Mafic versus Felsic 186 X-Ray Generation 160 Igneous Rocks 186 X-Ray Detection 162 Magmatic Processes 189 X-Ray Diffraction 162 Igneous Environments 189 Powder Method 163 Terrigenous Sedimentary Rocks 190 Sample Preparation 163 Sedimentary Processes 191 Instrumental Output 163 Sedimentary Environments 193 Data Reduction 164 Metamorphic Rocks 194 Powder Diffraction File 165 Metamorphic Variables 194 Bragg Reflection Indices 166 Metamorphic Processes 196. Mineral Identification 166 Metamorphic Grade, Fades, Mineral Zone Mixed Samples ~\67 Boundaries and Isograds 196, Estimation of Relative Mineral Abundance 168 Major Compositional Groups of Metamorphic Estimation of Composition 168 Rocks 198 Determining Unit Cell Parameters 168 Metamorphic Environments 199 x • Contents

References Cited and Suggestions for Additional Uses 256 Reading 200 Clay in the Environment 257 Other Sheet Silicates 257 Chapter 12: Framework Silicates 201 Stilpnomelane 257 Introduction 201 Prehnite 259 Silica Group 201 References Cited and Suggestions for Additional Quartz 202 Reading 260 Tridymite 206 Cristobalite 207 Chapter 14: Chain Silicates 261 Opal 208 Introduction 261 Feldspar Group 208 Pyroxene Group 261 Composition 208 Structure and Classification 261 Structure 209 Geology of Pyroxenes 263 Al/Si Order/Disorder 210 Orthopyroxene 265 Exsolution in the Feldspars 212 Low-Ca-Clinopyroxene 267 Other Feldspar Intergrowths 213 Calcic Clinopyroxene 268 Twinning 213 Aegirine (Acmite), Aegirine-Augite 269 Plagioclase 215 jadeite 271 K-Feldspar 220 Omphacite 273 Feldspathoids 225 Spodumene 273 Nepheline 225 Pyroxenoid Group 274 Leucite 227 Introduction 27 A Sodalite 227 Wollastonite 274 Zeolite Group 228 Rhodonite 274 Scapolite 232 Pectolite 276 References Cited and Suggestions for Additional Amphibole Group 277 Reading 234 Structure and Classification 277 Chapter 13: Sheet Silicates 235 Geology of Amphiboles 279 Orthoamphibole 280 Introduction 235 Cummingtonite-Grunerite 282 Structure and Classification 235 Tremolite-Ferro-actinolite 283 1:1 Layer Silicates 237 Hornblende 285 2:1 Layer Silicates 237 Glaucophane-Riebeckite 287 Polytypism 239 Other Amphiboles 288 70 Structures (1:1) 239 References Cited and Suggestions for Additional Serpentine (Antigorite, Chrysotile, Reading 289 Lizardite) 239 Kaolinite 242 Chapter 15: Disilicates and TOT Structures (2:1) 242 Ring Silicates 291 Talc 242 Pyrophyllite 243 Disilicates 291 TOT + c Structures: Mica Minerals (2:1) 244 Structure and Classification 291 Muscovite 244 Zoisite 293 Biotite 246 Clinozoisite-Epidote 294 Glauconite 248 Allanite 297 TOT + c Structures: Brittle Micas (2:1) 249 Lawsonite 298 Margarite 249 Pumpellyite 299 Clintonite 250 Ring Silicates 300 TOT + O Structure 251 Structure and Classification 300 Chlorite 251 Beryl 300 Clay Minerals 252 Cordierite 302 Structure and Classification 253 Tourmaline 303 Geology of Clay 255 References Cited and Suggestions for Additional Identification 256 Reading 305 Contents • xi

Chapter 16: Orthosilicates 306 Cuprite 356 Introduction 306 Ice 357 Olivine Group 306 XO Group 358 Garnet Group 310 XY2O4 Minerals 358 Zircon 312 Spinel Group 358 Aluminum Silicates 314 Magnetite 360 Chromite 361 w Andalusite 316 Sillimanite 318 Spinel Series 362 Kyanite 319 Chrysoberyl 363 Staurolite 319 X2O3 Group 363 Chloritoid 321 Hematite 364 Titanite 322 Corundum 365 Topaz 323 llmenite 366 References Cited and Suggestions for Additional XO2 Group 367 Reading 325 Rutile 367 Cassiterite 368 Chapter 17: Carbonates, Sulfates, Uraninite 369 Phosphates, Tungstates, Hydroxides 370 Molybdates, and Borates 326 Sri/dfe? 371 Iron Hydroxide Minerals 371 Structure and Classification 326 Aluminum Hydroxide Minerals 372 Carbonates 326 Manganese Oxide and Hydroxide Rhombohedral Carbonates (Calcite and Dolomite Minerals 372 Groups) 327 Halides 374 Calcite 329 Ho/;te 374 Magnesite 331 Sy/wte 376 Siderite 332 Fluorite 376 Rhodochrosite 333 References Cited and Suggestions for Additional Dolomite-Ankerite 334 Reading 377 Aragonite Group 335 Aragonite 336 Chapter 19: Sulfides and Related Witherite 337 Minerals 378 Strontianite 338 Introduction 378 OH-Bearing Carbonates 339 Crystal Chemistry and Classification 378 Malachite 339 Sulfide Paragenesis 379 Azurite 340 Hydrothermal Deposits 379 Sulfates 340 Supergene Processes 380 Gypsum 341 Sulfide Minerals 382 Anhydrite 344 Sphalerite 382 Barite 345 Galena 385 Phosphates 346 Pyrrhotite 386 Apatite 346 Chalcopyrite 387 Monazite 349 Cinnabar 388 Xenotime 350 Pynte 389 Tourquoise 351 Marcasite 390 Tungstates and Molybdates 352 Molybdenite 391 Borates 353 Bom/fe 392 References Cited and Suggestions for Additional Chalcocite 392 Reading 355 Covellite 393 Sulfarsenides 394 Chapter 18: Oxides, Hydroxides, Arsenopyrite 395 and Halides 356 Arsenides 395 Introduction 356 Tellurides 395 Oxides 356 References Cited and Suggestions for Additional X2O Group 356 Reading 396 xii • Contents

Chapter 20: Native Elements 397 Table B.7. Indices of Refraction of Isotropic Introduction 397 Minerals 417 Metals 397 Table B.8. Indices of Refraction of Uniaxial Gold 398 Minerals 418 Silver 399 Table B.9. Indices of Refraction of Biaxial Negative Copper 400 Minerals Arranged in Order of Increasing Semimetals 400 rip 419 Nonmetals 401 Table B.10. Indices of Refraction of Biaxial Positive Sulfur 401 Minerals Arranged in Order of Increasing Graphite 402 rift 420 Diamond 403 Table B.11. Minerals That Produce Pleochroic References Cited and Suggestions for Additional Halos in Surrounding Minerals 421 Reading 404 Table B.12. Colors Exhibited by Opaque Minerals in Polished Section Viewed in Air 421 Table B.I 3. Opaque or Nearly Opague Minerals APPENDICES That Display Internal Reflections with Reflected Light 422 Crystal Drawing Conventions 422 Appendix A. Effective Ionic Radii of the Elements 405 Appendix C. Mineral Associations 423 Appendix B. Determinative Tables 410 Table C.I. Mineralogy of Common Igneous Table B.I. Determinative Table for Nonmetallic Rocks 423 Minerals with White, Gray, or Other Pale Table C.2. Mineralogy of Sedimentary Colored Streak 410 Rocks 423 Table B.2. Nonmetallic Minerals with Distinctly Table C.3. Mineralogy of Common Metamorphic Colored Streak 414 Rocks 424 Table B.3. Minerals with Metallic and Submetallic Table C.4. Mineralogy of Hydrothermal Sulfide Luster 414 Deposits 425 Table B.4. Specific Gravity 415 Table B.5. Minerals That May Flouresce 416 Table B.6. Color of Minerals in Thin Section and Mineral Index 427 Grain Mount 416 Subject Index 433