This is a list of links to computer software available on other servers.  URLs are given where you can download software at no cost.  Commercial software is not included.  The link for each software title leads to the home page (if available); follow the compute (Mac) (PC)  links for direct downloads.

crystallographic, spectroscopic

• CRUSH - calculates the Rigid Unit Mode spectrum for a given framework crystal structure. by Martin Dove.
• EoSFit - to fit and manipulate equations of state, and other software for collecting and processing high-pressure single-crystal diffraction data. by Ross Angel.
• GALOPER is a computer program (written in Microsoft Excel macro language) which simulates the shapes of crystal size distributions (CSDs) from the crystal growth mechanisms discussed in Eberl, D. D., Drits, V.A., and Srodon, J., 1998, Deducing crystal growth mechanisms for minerals from the shapes of crystal size distributions. American Journal of Science, v. 298, p. 499-533. Measured CSDs are simulated with Galoper to discover crystal growth history. It available for downloading from the USGS ftp site: GALOPER.  by Dennis D. Eberl.
• GSAS (General Structure Analysis System) is a comprehensive system for the refinement of structural models to both x-ray and neutron diffraction data. The GSAS package can be used with both single-crystal and powder diffraction data (Rietveld analysis), even both simultaneously. Neutron data can be either from single-wavelength instruments, or for those a bit more masochistic, time-of-flight instrumentation. Up to 99 different sets of data can be modeled using mixtures of up to 9 different phases. GSAS has been created by Allen C. Larson and Robert B. Von Dreele of Los Alamos National Laboratory. Executable versions of GSAS are distributed more-or-less freely (see the friendly message from the Regents of the University of California at the site) from: http://www.ncnr.nist.gov/xtal/software/gsas.html.
• KALI Jeff Weeks' Topology and Geometry Software. Play with the 17 plane groups, the 10 point groups (plus 5-fold symmetry) and even symmetry along a line geometrygames.org. Click on Kali, and download the appropriate version. Easy to use, just start it and click away.
• MUDMASTER is a computer program (written in Microsoft Excel macro language) which determines mean crystallite size, crystallite size distribution and strain by Fourier analysis of X-ray diffraction peak shape. It is based on the Bertaut-Warren-Averbach technique, as has been described in Drits, V., Eberl, D. D., and Srodon, J., 1998, XRD measurement of mean thickness, thickness distribution and strain for illite and illite/smectite crystallites by the Bertaut-Warren-Averbach technique. Clays & Clay Minerals, v. 46, p. 38-50. The program is easy to use, and determinations are very accurate for nano-size crystals. It available for downloading from the USGS ftp site: MUDMASTER.  by Dennis D. Eberl.
• NMRFIT - deduce the short-range Al/Si order in a framework aluminosilicate mineral from Si MAS-NMR data by means of a Monte-Carlo simulated anneal. by Martin Dove. 
• UnitCell : Program to refine unit cell parameters from powder diffraction data. by Tim Holland.  Mac PC
• OccQP : Optimization of site-occupancies in minerals using quadratic programming, as described in the article by S.E. Wright, J.A. Foley, and J.M. Hughes (Am. Min., 2000). Written and maintained by Stephen E. Wright.

• AX - calculate activities for mineral end members. by Tim Holland. Mac PC
• ERUPT - graphical program that simulates various volcanic eruption types, including Strombolian, Plinian, Vulcanian/Surtseyan pyroclastic flows and surges, Hawaiian fluid lava flows, fumarolic activity, and Peléean viscous lava dome emplacement. Tectonic (faulting), caldera and sector collapse, and erosional events are also simulated. by Kenneth H. Wohletz.
• GIBBS - generalized Jacobean transformation algorithm designed to perform thermodynamic calculations of heterogeneous phase equilibria useful to metamorphic petrology.  The program is designed to produce graphical output of results (phase diagrams, P-T diagrams, etc.) and there are several modules sesigned to facilitate different types of phase equilibrium calculations, plus the notes from a short course given at the NEGSA meeting in  Burlington, Vermont in March, 2001. by Frank Spear. MAC
• GPT - Excel Spreadsheet for thermobarometric calculations in metapelitic rocks. by Reche & Martinez.
• GTB - Macintosh GeoThermoBarometry program. by Matt Kohn and Frank Spear.
• HEAT - 2-D, heterogeneous, heat flow simulator, useful for modeling magma chamber evolution. by Kenneth H. Wohletz.
• Hbplag - Program to calculate temperatures for hornblende-plagioclase assemblages.  by Tim Holland.  Mac PC
• MAGMA - Program to calculate the IUGG volcanic rock classification, CIPW norms, viscosity, and density of magmatic silicate liquids from chemical composition and temperature. by Kenneth H. Wohletz.
• MELTS - thermodynamic modeling of phase equilibria in magmatic systems. by Mark Ghiorso.
• NICHOLS - gar-cor-sp-sil/ky-qtz thermobarometry (on-line calculations). by Geoff Nichols
• OLIVERIAN - olivine thermobarometry. by Frank Spear. MAC
• PERPLE_X - petrologic phase equilibria. by James Connolly
• QUILF - Fe-Mg-Ti oxide-pyx-ol-qtz equilibria. by Andersen, Lindsley and Davidson MacUNIXDOS
• RockJock - a free program for calculating mineral weight percents from powder X-ray diffraction data, available for downloading from the following USGS ftp site: RockJock. The program is almost entirely automatic, requiring only that the X-ray intensities for a sample be entered into the program, that minerals likely to be present be chosen from a list, and that a button be clicked. The instruction manual (RockMan) is available from the same site.  by Dennis D. Eberl.
• SFT - graphical application designed to invert particle size data to find size distribution parameters of lognormal, sequential fragmentation, or sequential fragmentation/transport models, the latter two providing information about the fragmentation/transport origins of the sample (Wohletz et al., 1989, Jour Geophys Res 94: 15703-15721).  by Kenneth H. Wohletz.
• THERIAC-DOMINO - phase equilibria by free energy minimization. by Christian de Capitani. FORTRAN source codes .
• Tetplot - plotting tetrahedral phase diagrams. by Frank Spear.
• THERMOCALC - database for metamorphic phase equilibria. by Roger Powell and Tim Holland.
• TWQ - thermodynamic database for metamorphic phase equilibria. by Rob Berman. 
• UBC - retreivable mineral thermodynamic data. by Tom Brown.
• WEBINVEQ - on-line thermobarometric calculations. by Terry Gordon.