2. MichelLevy.zip: This file contains a movie that displays a Michel-Levy color strip with retardations that range from zero to 2400 nm. The color strip is included in several formats: MLevySpec.jpg, MLevySpec.pdf, MLevySpec.cdr, and MLevySpec.psd for those who want to construct charts with retardation as an axis.            
To run the two movies, you need the latest version of the Flash player from Adobe. You can download the Flash player by clicking on the icon:

 

To run the movies, open the *.html files with your favorite web browser.

3. Extinct.zip: This file contains a windows-executable file, Optics.exe, which you can use to calculate extinction angles. The program will run only on a PC or a windows partition. The program implements the procedures described in the *.pdf files and carries an extensive help system that can be accessed from inside the program.

4. Excel.zip: This file contains two spreadsheets. The first, Birefringence.xlsx, calculates the birefringence from the direction cosines of a known wave normal or you can elect to calculate the direction cosines from the known birefringence and a refractive index. These calculations come from equations derived by Wright (1923). The precision with which the birefringence can be calculated from the wave normal is strongly dependent on the precision with which the direction cosines are known. Usually, they should be known to at least five significant figures.
The second spreadsheet, MetricT.xlsx, calculates the angle between lattice planes, (h1k1l1) and (h2k2l2), or between lattice directions, [u1v1w1] and [u2v2w2]. The procedures use crystallography’s metric tensor (see Dyar, et al., 2008, Chapter 13.

5. PowerPnt.zip: This file contains a power point presentation describing the role birefringence can play in determining the orientation of biaxial crystal in thin section. I recommend you print the notes and read along as you go through the presentation.