100 Ferguson and Merwin — The Ternary System. 



mite, and 5Ca0.2Mg0.6Si0 2 . It has a composition 

 CaO 30-6, MgO 8, Si0 2 614, and a temperature 

 1320 ± 5°C. 



Table III. 

 Quenches which determine the temperature relations at point 1. 



Time 



Composition 

 2aO MgO 



wt. % 

 SiO, 



Temp. 

 °C. 



in 



min. 



Phases present 



31 7 



62 



1324 

 1319 



20 

 45 



Glass -\- crystals 

 No glass 



31 9 



60 



1321 

 1316 



15 

 15 



Glass -|- crystals 

 No glass 



32 7 



61 



1319 



20 



No glass 



32 8 



60 



1324 

 1315 



25 

 20 



Glass -L. crystals 

 No glass 







1320 



20 



Glass -}- crystals 



Point 16 is a non-entectic at which tridymite, a wollas- 

 tonite solid solution, and a 5Ca0.2Mg0.6Si0 2 solid solu- 

 tion can co-exist with a liquid. The temperature and 

 location of this point have not been separately deter- 

 mined. It lies very close to point 15 with a probable 

 temperature of 1330 ± 5°C. 



Point 15 is a non-eutectic between pseudowollastonite, 

 a wollastonite solid solution and tridymite. It occurs 

 at the composition CaO 31-3, MgO 7-2, Si0 2 61-5, and its 

 temperature is 1335 ± 5°C. 



Table IV. 

 Quenches which determine the temperature relations at point 15. 

 Time 



Composition 



wt. % 



Temp. 



in 



Phases present 



CaO MgO 



Si0 2 



°C. 



min. 





31 7 



62 



1343 



20 



Glass + SiO, 







1338 



20 



Glass -L SiO, -f aCaO.SiO, 



32 6 



62 



1339 



20 



Glass + SiO, + aCaO.SiO, 







1334 



20 



Glass + Si0 2 + (jSCaO.SiO, or 



5CaO.2MgO.6SiO,) 



32 7 



61 



1331 



20 



Glass -f SiO, + (/3CaO.SiO, or 



5CaO.2MgO.6SiO,) 







1337 



20 



Glass + aCaO.SiO, 



Point 14 39 is a quintuple point between pseudowollas- 

 tonite, a wollastonite solid solution, and a 5Ca0.2Mg0. 

 6Si0 2 solid solution. It has a composition CaO 314, 

 MgO* 7-6, Si0 2 61, and a temperature of 1340 ± 5°C. 



Point 13 is a quintuple point between pseudowollaston- 



39 The location and temperatures of points 14 and 13 will be discussed 

 under the wollastonite and 5CaO.2MgO.6SiO, solid solutions. 



