Optical Mineralogy Principles and Practice

This book is the successor to A practical introduction to optical mineralogy, which was written in the early 1980s, and published by George Allen & Unwin in 1985. Our intention, once again, is to introduce the student of geology to the microscopic examination of minerals, by both transmitted and reflected light. These techniques should be mastered by students early in their careers, and this text has been proposed in the full awareness that it will be used as a laboratory handbook, serving as a quick reference to the properties of minerals. However, care has been taken to present a systematic explanation of the use of the microscope, as well as to include an extended explanation of the theoretical aspects of optical crystallography in transmitted light. The book is therefore intended as a serious text that introduces the study of minerals under the microscope to the intending honours student of geology, as well as providing information for the novice or interested layman.

1 Introduction to the microscopic study of minerals.- 1.1 Introduction.- 1.2 The transmitted-light microscope.- 1.3 The appearance of thin sections using transmitted-light microscopy.- 1.4 Systematic description of minerals in thin section using transmitted light.- 1.4.1 Properties in plane polarized light.- 1.4.2 Properties under crossed polars.- 1.5 The reflected-light microscope.- 1.6 The appearance of polished sections under the reflected-light microscope.- 1.7 Systematic description of minerals in polished section using reflected light.- 1.8 Observations using oil immersion in reflected-light studies.- 1.9 Polishing hardness.- 1.10 Microhardness (VHN).- 1.11 Practical points on the use of the microscope (transmitted and reflected light).- 1.12 Preparation of thin and polished sections.- 2 Silicate minerals.- 2.1 Crystal chemistry of silicate minerals.- 2.2 Mineral descriptions.- 3 The non-silicates.- 3.1 Introduction.- 3.2 Arsenides.- 3.3 Carbonates.- 3.4 Halides.- 3.5 Hydroxides.- 3.6 Native elements.- 3.7 Oxides.- 3.8 Phosphates.- 3.9 Sulphates.- 3.10 Sulphides.- 3.11 Tungstates.- 4 Transmitted-light crystallography.- 4.1 Introduction.- 4.2 Refraction.- 4.3 The refractive index.- 4.4 The Becke effect and the Becke line.- 4.5 Birefringence and Newton’s Scale of Interference Colours.- 4.5.1 Anomalous interference colours.- 4.6 Isotropic and anisotropic minerals.- 4.7 The isotropic indicatrix.- 4.8 The uniaxial indicatrix.- 4.9 The biaxial indicatrix.- 4.10 Pleochroism.- 5 Reflected-light theory.- 5.1 Introduction.- 5.2 Colour of minerals in PPL.- 5.3 Isotropic and anisotropic sections.- Appendix A Refractive indices.- Appendix B 2V size and sign of biaxial minerals.- Appendix C Properties of ore minerals.- Appendix D Mineral identification chart.- Appendix EGangue minerals.