AN INTERACTIVE SPREADSHEET FOR GRAPHING MINERAL STABILITY DIAGRAMS

The assessment of mineral stability during water-rock interactions is critical for defining element mass balances. One method of assessing t he relative stability of minerals in a solution of known elemental con centration and pH is the mineral stability diagram. The positioning of lines representing the stability of minerals on a plot of log(10)(Al3 +)+3pH versus log(10)(H4SiO4 degrees) depends on the chemical composit ion of the minerals as well as their free energy of formation. Lack of correspondence between reported heats of formation from different sou rces has been the motivation for generating this spreadsheet routine. By using this spreadsheet which instantly plots the position of stabil ity lines on the active spreadsheet screen, the effect of changing val ues of thermochemical data, pH, and temperature on sample stability ca n be assessed.