In this page GSF just wants to suggest some open source software useful in geosciences.
You find a short software description and links where you can download it for free. GSF has not any relation with the developers or the companies

GEOrient v9.x plots and analyses stereographic projections and rose diagrams of geological structural data, copied and pasted from other applications, or read from text files. The limit on the number of data is system memory and resources.

GVsig is a geographic information system (GIS) designed for capturing, storing, handling, analyzing and deploying any kind of referenced geographic information in order to solve complex management and planning problems. gvSIG is known for having a user-friendly interface, being able to access the most common formats, both vector and raster ones. It features a wide range of tools for working with geographic-like information (query tools, layout creation, geoprocessing, networks, etc.), which turns gvSIG into the ideal tool for users working in the land realm.

LandSerf is a freely available Geographical Information System (GIS) for the visualisation and analysis of surfaces. Applications include visualisation of landscapes; geomorphological analysis; gaming development; GIS file conversion; map output; archaeological mapping and analysis; surface modelling and many others. It runs on any platform that supports the Java Runtime Environment (Windows, MacOSX, Unix, Linux etc.)

PHREEQC One of the most used program for Speciation, Batch-Reaction, One dimensional transport and Geochemical Calculations. If you work in hydro chemistry you must know it!

Visual MINTEQ is a freeware chemical equilibrium model for the calculation of metal speciation, solubility equilibria, sorption etc. for natural waters. It combines state-of-the-art descriptions of sorption and complexation reactions with easy-to-use menus and options for importing and exporting data from/to Excel. Chemical equilibrium modelling has never been easier!

CrunchFlow Multicomponent Reactive Flow and Transport Software. is a software package for multicomponent reactive flow and transport that was developed over about 20 years by Carl Steefel (now at Lawrence Berkeley National Laboratory). The software can be used for simulation of a range of important processes and environments, including reactive contaminant transport, chemical weathering, carbon sequestration, biogeochemical cycling, and water-rock interaction.

Visual Retraso (REactive TRAnsport of SOlutes, Visual version) RETRASO simulates transport processes (advection, dispersion and diffusion) and chemical reactions (acid-base reactions, redox, complexation, adsorption, cation exchange, precipitation and dissolution of minerals). Chemical reactions can be assumed to follow either an equilibrium or a kinetic approach. The numerical solution is carried out using the global implicit or direct substitution approach. That means that all equations are solved simultaneously by applying Newton-Raphson

Easy_Quim easy excel file to calculate chemical balances in water, you can automatically make graphs like Piper, Siff, Schöeller and Salinity Diagrams

ImageJ is a public domain Java image processing and analysis program. It can read many image formats including TIFF, GIF, JPEG, BMP, DICOM, FITS and ‘raw’. It supports ‘stacks’ (and hyperstacks), a series of images that share a single window. With this program you can calculate areas, vaolumes,distances, angles, 3D reconstructions, tomography and microtomography calculations….It is a very powerfull tool, user friendly and constantly developing. Nice user manual and wiki page with video tutorials examples

WSxM Nanotec free software for Processing images from Scanning Probe Microscopy and Atomic Force Microscope (only for Windows). Very user friendly, easy to learn and extremely intuitive. You can make every kind of calculation, measurements, analysis on SPM and AFM images