Figure 02. Aluminosilicate G-T Diagram.

This diagrams shows the Gibbs energies of the three aluminosilicate polymorphs kyanite (blue), sillimanite (black), and andalusite (rose). The diagram and data are derived from the thermodynamic model dataset SPaC (version 2015) developed originally by Spear and Cheney (1989), which uses the Pattison (1992) triple point. Use the slider to change the pressure. Notice that the Gibbs energy differences between the phases are small relative to the sizes of the numbers. Gibbs energy values vary more strongly with temperature, than with pressure.

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