171 JSf. L. Botoen — Crystallization of Haplobasaltic, 



from the liquid first and is later joined by diopside, the tem- 

 perature at which diopside appears marking the border of the 

 three-phase area. In AfyAn, 85 per cent-diopside 15 percent, 

 diopside first appears at 1216° ; in Ab 44 An 66 75 per cent-diop- 

 side 25 per cent, at 1230°. 



ANORTHITE 



Fig. 10. Three-phase-boundaries. 



In fig. 10 the determined three-phase-boundaries are drawn 

 in full lines and numbered according to the method of deter- 

 mination. In dotted lines the theoretical general direction 

 of others is shown. A three-phase-boundary intermediate 

 between two that are determined may be found by interpola- 

 tion. 



Crystallization of Mixtures in the Diopside Field. 



Three-phase-boundaries being located, the course of crystal- 

 lization (with perfect equilibrium) of any mixture whose com- 

 position is represented by a point in the diopside field can now 

 be quantitatively described. Thus in fig. 11 the mixture F 



