MINERALOGY + LABORATORY OF MINERALOGY
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- Versione italiana
- Academic year
- 2021/2022
- Teacher
- GIUSEPPE CRUCIANI
- Credits
- 12
- Didactic period
- Annualità Singola
- SSD
- GEO/06
Training objectives
- This course is based on the concept that geological processes can be understood and interpreted through the study of minerals (the “alphabet” of Geology) making rocks (the “words” of Geology). Thus this course is aimed to provide students with fundamental skills on symmetry, crystal-chemistry and mineral systematics (“Mineralogy” part), and on interactions of visible light and X-rays with minerals (“Mineralogy Laboratory” part) along with the abilities to identify and describe minerals in most of the geological occurrences and in formation and transformation in both natural and artificial processes.
The main knowledge acquired by the students include:
basic concepts of solid and crystalline state;
fundamental skills of crystallography and symmetry;
fundamental concepts of crystal-chemistry;
descriptive knowledge of the major groups of ‘rock forming’ minerals;
understanding of the visible light propagation and related phenomena in minerals
understanding of the X-ray interactions with minerals and related phenomena.
The main abilities acquired by the students include:
symmetry determination of a bi- and tri-dimensional simplified pattern;
crystal-chemical formula calculation of the major ‘rock-forming’ minerals;
ability to perform the main types of observation for identification of minerals in thin sections using a polarized light optical microscope;
interpretation of X-ray diffraction analyses. Prerequisites
- Basic knowledge acquired during the high school and/or from attendance of courses in Mathematics (basic vector properties and operations; main trigonometry functions; basics of complex numbers), Chemistry (quantum theory and electronic structure of atoms. Elements and Periodic table; atomic and molecular weights, moles; first ionization energies, electronegativity and oxidation numbers; chemical bond; phase equilibria and chemical equilibrium; principles of thermodynamics; Gibbs'free energy), Physics I (scalars and vectors; measurement units; potential and mechanical energy; specific heat and thermal capacity; principles of thermodynamics), Geology I (Earth’s interiors; introduction to igneous, metamorphic and sedimentary rocks and processes), and Physics II (basics on electric and magnetic fields).
Course programme
- The joint course of Mineralogy and Laboratory of Mineralogy is structured in two modules, 60 hours each, encompassing theoretical lectures and guided tutorial on exercises.
Module I (Mineralogy): Amorphous and crystalline states. Periodically homogeneous distribution of atoms in crystals. Lattice planes and 5 types of simple and multiple tiles. The 3D lattice and its properties. The unit cell. Mirror line and proper rotation axes. Rotations allowed in a periodic lattice. The 10 2D point groups. Glide lines. The combination of 10 2D point groups with the 5 tiles: the 17 plane groups. [group of topics I-1a: 13 hours] Crystallographic axial systems. The 14 Bravais lattices. The crystal systems. Symmetry in 3D: inversion centre, mirror plane, proper and improper rotation axes. Coexistence of symmetry operators. The 32 point groups. Crystal morphology. Relation between crystal lattice and morphology. Miller indexes. Simple and combined crystal forms. The stereographic projection of 32 point groups. Glide planes and screw axes. The 230 space groups: derivation for the 13 monoclinic space groups. General properties of space groups. Space groups and crystal structures. [topics I-1b: 28 hours] Basics of chemical bond. Nominal valence. Ionic radii (Shannon). Goldschmidt and Laves principles. Close-packing of rigid spheres. Coordination number and polyhedra. Pauling rules. Isomorphism and solid solution diagrams. Polymorphism and phase diagrams. Twinning and crystal defects. Physical properties of minerals. Mineral origin. Principles of classification of minerals and silicates.[group of topics I-2a: 16 hours] Descriptive mineralogy of orthosilicates (olivines, garnets, anhydrous Al silicates), single chain silicates pyroxenes), double chain silicates (amphiboles), layer silicates (including micas), framework silicates (silica, feldspars, feldspathoids and zeolites), oxides (spinels) and other groups (hydroxides, sulfides, carbonates, sulfates, phosphates, halides).[topics I-2b: 17 hours]
Module II: Basics of the electromagnetic radiation, visible light, and waves. Isotropic media optics (reflection, refraction, Snell law). Refraction index. Light polarization. Light absorption (Lambert-Beer law; colour and pleochroism; crystal field, charge transfer and band theories). Optically isotropic and anisotropic media. The polarizing optical microscope. Birefringence (calcite rhombohedron experience; ordinary and extraordinary rays and plane waves; structure-light propagation relationship). Optical indicatrix (uniaxial, biaxial, Neumann principle, optical axes). Interference colours (quartz wedge experience, retardation, equation of wave at the analyzer, Michel-Levy table, compensators). Interference figures. Optic sign determination. Guided tutorials on the optical microscope.[topics II-1: 17 hours] Introduction to crystal structure analysis of minerals. X-ray sources (X-ray sealed tube; emission spectra; basics of synchrotron radiation sources). X-ray interaction with matter (Rayleigh elastic scattering; Compton inelastic effect; photoelectric effect). Wave equation as complex number (basics of Fourier transform). Theory of X-ray diffraction (scattering factor; Laue equations; Bragg's law; reciprocal lattice and its relations with direct lattice; Ewald sphere; structure factor; the phase problem; systematic absences). Techniques for X-ray crystallography (X-ray detectors; basics of single crystal methods; theory of polycrystalline sample diffraction; automated diffractometers). Guided tutorial on a single crystal and polycrystalline (powder)X-ray diffractometer. Interpretation of powder diffraction patterns: phase identification and peak indexing. Exercises of powder diffraction patterns.[topics II-2: 17 hours] Didactic methods
- Frontal lectures in the classroom (and/or remote teaching), on all the course’s topics, with the aid of on-screen presentation and blackboard work. Students are regularly asked to assess their understanding.
Guided tutorials on exercises in the classroom (and/or remote teaching) on topic groups I-1a, I-1b, I-2b e II-2 (tutorials are also held with the help of tutors; the teacher/tutor delivers exercise materials, students work individually or in groups, the teacher/tutor assists the student in the exercise development and verify the correctness of solutions; materials for homework exercises are also given to students)
Practical training at the Optical Microscopy Laboratory (and/or with recorded videos) on topic group II-1 (teacher explains the type of observation to be performed and helps the students to became operational with the optical microscope)
Practical training at the X-ray Diffraction Laboratories (powders and single crystal) and/or with recorded videos on topic group II-2 (the teacher/tutor describes to the students the complex instrumentation then explains and manages the data collection operation; students are then engaged in the preliminary interpretation of collected data). Learning assessment procedures
- The aim of the assessment procedures is to check the achievement level of the previously described learning objectives (knowledge and abilities) during and at the end of the course.
Four tests are planned covering the topic groups I-1a+b (1st test), I-2a+b (2nd test), II-1 (3rd test) and II2 (4th test): the 1st test (typically, beginning of November) includes 8-9 questions of which four exercises (Miller indexes, plane group, stereographic projection, space group); the 2nd test (January) includes 12-15 questions of which one exercise (crystal-chemical formula calculation); the 3rd (mid April) and 4th (mid June) include 8 questions each. The tests are typically in written form. Each written test is allocated 2-2 ½ hours. Alternatively, tests can be performed as orals, online, and as quiz with multiple answers. Recovery tests are planned in February and June. The test assessment results are communicated to students at the end of the teaching modules (i.e. within the exam term January-February for the 1st and 2nd tests, in June-July for the 3rd and 4th tests). Written (or oral) tests are assessed with grades on a scale of 31 and grouped in three categories: i) passed with a sufficient grade (> 18 or higher), ii) not passed with a slightly insufficient grade amendable by an oral examination, and iii) not passed with a largely insufficient grade. Each ongoing written test can be replaced by an oral examination on the same group of topics. Added to the four (written or oral ongoing test) a final written examination deals with an exercise on the diffraction pattern. The final mark given to the student is calculated as the average of the four passed ongoing tests, weighted by ¾, and the diffraction pattern test, weighted by ¼. Reference texts
- File versions of the on-screen presentations used by the teacher for lectures and made available on the course webpage. Powerpoint video presentations, audio-commented by the teacher and accessible on the online platform.
Useful books:
BONATTI e FRANZINI - Cristallografia mineralogica - Boringhieri, 1984.
GOTTARDI - I minerali - Boringhieri, 1992
KLEIN - Mineralogia - Zanichelli, 2004
PUTNIS - Introduction to Mineral Sciences - Cambridge University Press, 1992
MAZZI e BERNARDINI - Fondamenti di Cristallografia e Ottica Cristallografica - USES, 1983.
Suggested books for further readings on specific topics:
BORCHARDT-OTT - Crystallography - Springer Verlag.
NESSE - Introduction to Optical Mineralogy - Oxford University Press, 1991.
