Results from a McCrone Spindle Stage Short Course, a New Version of EXCALIBR, and How to Build a Spindle Stage

This paper discusses the results of a 3-day short course in spindle stage techniques recently offered at the McCrone Research Institute. The 14 students enrolled had levels of experience with spindle stage and optical crystallography which varied from novice to expert, but all were soon able to collect research quality crystallographic data on crystals less than 100 μm using a simple, home-made poster-board spindle stage and the newest version of EXCALIBR, EXCALIBRW. EXCALIBRW is Windows compatible, free, and has three major improvements over the previous version: 1) easier data entry, 2) a refinement method for the calculation of the reference azimuth, and 3) a more robust numerical solution to the Joel equations for determining the orientation of the optical indicatrix. Advantage (3) now allows the solution of extinction data for crystals in less favorable orientations. Also, during the course, the students built their own spindle stages from poster-board.