258 MANGANESE DEPOSITS OF INDIA : GEOLOGY. [ PaRT II 
I have converted the alkalies into orthoclase and albite. 
composition of these two rocks works out as follows : — 
Kotakaira l ock. Boiranirock. 
A. 233 A. 134 
The mineral 
Apatite 
K2O 
3-70 
0-01 
Apatite 
Orthoclase : 
K2O 
AI2O3 
Si02 
4 00 
4 -33 
15 -38 
2-87 
Na20 
0"18 
Albite :— 
NagO 
AI2O3 
Si02 
23-71 . 
0-36 
0-59 
2-10 
23 *71 
Mansanese-sarnet : — 
MnO" 10-00 
FeO 4-51 
CaO 9 -57 
MgO 0-14 
AI2O3 11-50 
Fe203 2-10 
Si02 22-7(5 
3-05 
Manganese-garnet : — 
MnO 1 -07 
FeO 0 -86 
CaO ]2'24 
MgO 0 -26 
AI2O3 5 -67 
Fe203 4 -55 
SiOa 15 -22 
3*05 
Oi)al: — 
Si02 
H2O 
(iO -58 
31 -39 
1 33 
GO -58 
Opal:— 
Si02 
H2O 
39-87 
27 -IMJ 
1 -20 
39-87 
Ti02 
CuO 
Moisture . 
Surxjlus oxygeu 
32-72. 
32 "72 
0-32 
0-02 
2-30 
0-36 
29-10 . 
Ti02 
CuO 
Moisture . 
Surplus oxygeu. 
29-10 
0-27 
trace 
1 -30 
0-02 
100 19 
100-19 
From each of the above analyses we can extract an analysis of the 
manf;anese-garnet by mialtiplying each of the constituents of the garnets 
by g^'.fg in the case of the Kotakarra rock and by in the case of the 
Boirani rock. The results obtained are as follows : — 
-MnO 
FoO 
CaO 
-MgO 
AI2OS 
Fe20? 
S1O2 
The Kotakarra 
garnet. 
10-50 
7-45 
15-80 
0-23 
18-98 
3-47 
37 '67 
The Boirani 
garnet. 
. 2 68 
. 2-16 
. 30-70 
. 0-65 
. 14-22 
. 11 -41 
. 38-18 
100 00 
100-00 
