Construct mineral equilibrium diagrams (at 25° C and 1 atmosphere)
for the following mineral assemblage: gibbsite, quartz, kaolinite, halloysite,
microcline, muscovite and albite. Use the free energies of formation given
in the table below. For each case below, calculate the stability boundaries
between __all mineral pairs__ and plot them on a diagram. Then determine
which sections of the boundaries are stable and redraft a second diagram
with the stable fields labeled. Show all your calculations and annotate
your procedure

__Case 1.__ Choose log *a*K^{+} / H^{+} as your
abscissa and log *a*Na^{+} / H^{+} as your ordinate
for the diagram. Assume the activity of the dissolved silica is fixed at
quartz saturation (*i.e.*, assume the solution is in equilibrium with
quartz).

__Case 2.__ Choose log*a*K^{+} / Na^{+} as your
abscissa and log *a*H^{+} as your ordinate for the diagram.
Assume the activity of the dissolved silica is fixed at quartz saturation
.

Table 1: Free energies of formation in kJ mol^{-1}, at 25°
C, 1 atmosphere pressure.

Phase |
DG |

gibbsite | -1154.916 |

halloysite | -3780.713 |

kaolinite | -3799.364 |

quartz | -856.288 |

muscovite | -5600.670 |

microcline | -3742.330 |

albite | -3711.722 |

water | -237.140 |

Na^{+} |
-261.900 |

K^{+} |
-282.490 |

H_{4}SiO_{4}^{o} |
-1308.000 |