Pure Fractional Crystallization

For pure fractional crystallization, all initial liquids, regardless of their starting compositions, will yield a solid mixture of En + Qtz, in the proportions represented by the eutectic composition. The final liquid present following a path of pure fractional crystallization will have a composition of the eutectic

For Batch fractional crystallization the composition of the last liquid and the solid phases present when crystallization has ceased will be dependant on where the last batch of crystals were removed along the path followed.

In the example shown in the above link, fractionation occurs at X2 and X5, leaving a final liquid composition of X6 and a final solid mixture of En + Qtz.

The fractionation at X2 removes forsterite and produces a dunite, fractionation at X5 removes En and results in a pyroxenite. The final solid mixture of En + Qtz produces a norite.