Cunnincuam—Orystallization of Minerals in Igneous Rocks. 397 
Q, 
Cc * th yd 
Mg 0 Oxides M.P. Alloys Walto || | 
Mg 0 2600(2)| Mg0,si0, 1800 
len es ae CaO 2500 Ca 0,8i 0, 1205 
ALO 2250 1090 
44+ 23 Al,0,,8i 0, { Wa a 
|_\ TiO, 1560 
ea) Si 0, 1425 | (¢a0 Sid) TiO, \1185 
(ule (ca0 SiO) (Mgosio,\i797 |_ 
Al,0, au (ca0si9)(mgosio)|1227 |__ 
\ ViPS heal ea 
\ a 
\ 
2000° \\— Lae 
\\ 
\\ 
\ 
\\ 
\v 
ENG a) 
\\ 
HAN - 
\\ 
\\ 
vy TiO, 
\h a 
1500 \ 
\ | ] SiO 
1400° \\ FA, 
\ \\ 1 Za | 
I ie Ziail 
1300° eae enstntitA A Lt Mg 0 Si 0,\(2) 
I 3 — 7 
1200° Cel (DOG, ee) Jel) Waplastonite Za Tremolite 
\ Didpsidé eae 
Pan Poa a 
1100° a 
| Cyanite 
4000° 
100 90 80 70 60 50 40 30 20 10 0 
0) 10 20 30 40 50 60 70 80 90 100 
Fic. 7.—Curves showing the Melting Points of certain ‘‘ Alloyed’’ Oxides which ©; 
occur as Rock-forming Minerals. 
