MINERALOGY LABS: AN INTEGRATED APPROACH (Invited Presentation)

Teaching mineralogy has changed dramatically following the workshops of 1996, 2011, and the incorporation of new pedagogy. Lecture texts now proceed from the concrete to the abstract, however, topics are still covered in specific chapters, e.g physical and chemical properties, crystallography, X-ray and finally optical. In lab, students move rapidly from the physical properties that they are vaguely familiar with from the introductory classes rapidly to new concepts and techniques. I approach the lab with the concept of “Just-in-time” knowledge, building up their skills little by little in multiple topics. By lab 2, they have handled and identified by physical properties 30 basic minerals. Then isotropic minerals, (halite, galena, garnet) with mirror planes and 2,3,4 fold axes only on cubes and octahedra, and simple microscope work. Then moving to uniaxial, focusing on quartz, calcite and tourmaline in hand sample and under the microscope. We correlate birefringence, ε and ω, pleochroism and the c-axis, seeing selected uniaxial figures, tetrahedral and hexagonal systems, mirror planes, and 2,3,6 fold axes. Then biaxial, feldspars, pyroxenes, olivines, amphiboles, and micas, finishing the crystal systems and correlating the crystal system and symmetry with the optics and hand samples. We then move on to a computer / Escher lab on symmetry, a carbonates lab, and an economic mineral / opaque’s lab. In the second part of the course, students are systematically introduced to the silicates. It is here I add rotoinversion, H-M symbols, steronets, Miller indicies, etc. By this time they are so familiar with simple symmetry, both blocks and minerals, that they simply accept these are easy ways to write down what they know. Introducing H-M is a classic “a-ha” moment. Errata: I keep peanut and plain uniaxial candy in the lab – to relieve stress!