The Calcite - Aragonite Phase Diagram

The simplest type of phase diagram involves a single component that can exist in more than one crystalline form, that is, a mineral having two or more polymorphs. For example, CaC03 can exist either in the form of calcite or aragonite. Using the equations we have derived, we can calculate either p or A Gp p for both 

Then we can examine these values of A G. Where A G is negative, evidently 

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Figure 6.8 The form of the calcite-aragonite phase diagram deduced from LeChatelier s principle.

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