Program Optics can be used to calculate optical properties of minerals. If you know the direction of a wave normal in either the optical indicatrix or in the crystal lattice, the program can calculate the extinction angle, birefringence, and indices of refraction you should see in a biaxial mineral. The theory behind the program can be found in the Optical Mineralogy section of Theory and Analysis.

Download Procedures
If you are using Microsoft Internet Explorer or Netscape Communicator, then versions of the programs that run under Windows can be downloaded clicking here: OpticsProg.exe. There are no versions that run on a Macintosh. OpticsProg.exe is a self-extracting file. All you have to do is run the file after downloading. After downloading the self-extracting file, move it to the directory where you want to keep Program Optics. Then run OpticsProg.exe. When the extraction is finished you should have four files in the directory: OPTICS.exe, a help-file: OPTHLP.HLP; and two data files: OPTICS.TXT and OPTICS.CST.