The Binary System Akermanite-Gehlenite. 135 



Composition Temperature Time 



wt. present. in degrees in 



Gehlenite. Akermanite. Centigrade. minutes. Phases present. 



20 80 1415 15 Glass 



1404 15 Glass 



1400 15 Glass -f- crystals 



1397 15 Glass -j- crystals 



1394 15 All crystals 



25 75 1390 15 Glass + trace 



crystals** 



1388 15 Glass + crys- 

 tals** 



1386 20 Trace glass + 



crystals 



1385 45 Crystals 



30 70 1397 15 Glass 



1394 15 Glass + crystals 



1392 15 Glass + crystals 



1390 15 Crystals 



40 60 1437 15 Glass 



1432 15 Glass 



1430 15 Glass + crystals 



1406 15 Trace glass + 



crystals 



1404 15 Trace glass + 



crystals 



1400 15 Crystals 



1396 15 Crystals 



50 50 1475 15 Trace crystals 



1478 15 Glass 



60 40 1517 15 Glass 



1512 15 Glass 



1506 15 Glass -f- crystals 



1488 15 Glass + crystals 



1460 15 Glass + crystals 



1445 15 Glass + crystals 



1441 15 Crystals 



80 • 20 1560 15 Glass 



1557 15 Glass 



1553 15 Glass + crystals 



1550 15 Glass + crystals 



1541 - 15 Glass + crystals 



1535 15 Glass -f" crystals 



1524 15 Glass + crystals 



1510 15 Glass + crystals 



1502 15 Glass + crystals 



1498 15 Crystals 



* The initial material was crystallized by long heating previous to use 

 because of the tendency of the glasses to undercool. 



** Simultaneous experiment with diopside gave all crystals. 



