A simple method to create mineral mounts in thin section for teaching optical mineralogy

Mineral separates mounted in thin section help introduce mineralogy students to concepts of relief, color, pleochroism, and birefringence and serve as reference materials both for research and teaching. Here, a simple method is described to produce materials that can be sent to thin section manufacturers to construct sets of mineral mounts. The method is relatively inexpensive, requires only simple equipment and few skills, and allows mounting of multiple minerals (easily 10-20) in a single thin section. The key to the method is to create first a slurry of 500-1000 mg of each crushed mineral plus ∼300 mg (500 μL) of epoxy and use a microspoon spatula to spoon each slurry into a 4 cm long tube made from 6 mm (or ¼″) diameter, standard wall, glass tubing. After epoxy sets, the 4 cm long tubes can be bundled together and shipped to thin section makers, who can set the bundles in epoxy (ends down) and make 10 or more duplicate sections. Photomicrographs are presented for selected mineral reference slides produced by this method, along with detailed instructions on how to create them. These methods allow both randomly oriented mineral separates and oriented crystals to illustrate isotropic appearance in quartz and reverse pleochroism in tourmaline.