Mineral Identification via Remote SEM Analysis

Sven Holbik and Rosemary Hickey-Vargas

Florida International University

This activity is part of the On the Cutting Edge Peer Reviewed Teaching Activities collection.

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Scientific Accuracy
Alignment of Learning Goals, Activities, and Assessments
Pedagogic Effectiveness
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This page first made public: Nov 18, 2014

Summary

Mineral Analysis, X-ray Techniques | College Lower (13-14), College Upper (15-16)

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Context

Audience

This exercise is used in a sophomore or junior level course in Mineralogy.

Skills and concepts that students must have mastered

Students must have some background in electron microscopy including the generation and detection of secondary electron, backscattered electrons, the generation of characteristic x-rays and the EDS detector. Students must understand idealized chemical formulas for minerals.

How the activity is situated in the course

This lab works well as an introductory assignment for students in a Mineralogy course. The introduction of electron microprobe instrumentation techniques and mineral chemistry works as a foundational starting point for students as they navigate to more challenging work in the Mineralogy-Petrology sequence of courses. This activity familiarizes the students with analytical techniques en route to potentially becoming proficient users of electron microprobe technology.

Goals

Content/concepts goals for this activity

The goal of this activity is to introduce students to the theory of electron microprobe analysis and x-ray analysis techniques, introduce students to new technology and instrumentation, understand mineral formulas/associations and compositions, and using qualitative EDS analysis to determine the elements found in minerals in their relative proportions.

Higher order thinking skills goals for this activity

Other skills goals for this activity

Description of the activity/assignment

This lab uses the remote capabilities of a scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS) available through the Florida Center for Analytical Electron Microscopy (FCAEM; http://fcaem.fiu.edu) at Florida International University in Miami, to explore mineral chemistry in a Mineralogy course. This instructor-guided interactive whole-class demonstration of the SEM with EDS analysis introduces students to microprobe analysis, new technology and instrumentation, x-ray analytical techniques, image analysis, mineral formulas and mineral composition. More specifically, the instructor will acquire images and take x-ray spectral data of unknown mineral mounts and students must use the spectral data to identify the minerals. This activity provides an exciting visual output and hands on approach that elevates student's interest and advances their analytical skills as well as introduces key concepts in mineralogy and chemistry.

Determining whether students have met the goals

If the students have correctly identified all minerals using the images, spectral data and mineral formulas then the goals of the assignment have been met.

More information about assessment tools and techniques.

Teaching materials and tips

Activity Description/Assignment (Acrobat (PDF) 511kB Nov18 14)
Instructors Notes: The in-class instructor lead demonstration and collection of x-ray spectra (using EDS) of unknown samples (up to 9 samples) may take between 30 to 45 minutes. Remote users of SEM & EDS at Florida Center for Analytical Electron Microscopy (FCAEM) can customize unknown samples used for demonstration given that the remote user has shipped samples to the center. Video tutorials are available for remote use of SEM with EDS at fcaem.fiu.edu/tutorials/. Users are encouraged to schedule practice time on the SEM with or without FCAEM staff guided help. A practice run through with the SEM will give the remote user a good approximation of how long the lab activity will take.