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MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ PaRT I : 
Consequently I have giv^en below the composition of braunites corres- 
ponding to ratios of 3:1, 7 : 2 and 4:1, respectively : — 
Formula. 
3Mn203. MnSiOs- 
7Mn203. 2MnSi03. 
4Mn203. IVInSiOs 1 
MnO .... 
46-91 
46-69 
46-51 
Mn02 .... 
4311 
44-49 
45-58 
Si02 .... 
9-98 
8-82 
7-91 
100-00 
100-00 
100 00 
Manganese 
63-59 
64-29 
64-85 
Available oxgyen . 
7-93 
8-18 
8-38 
Or, if the manganese and oxygen be stated in terms of MnO and Mn20j, 
the figures are as follows : — • 
MuO .... 
11-73 
10-38 
9-30 
Mn203 
78 29 
80-80 
82-79 
On comparing with these figures the analyses of Indian braunites given 
above it appears that the Garividi specimen corresponds almost exactly 
to a formula lying half-way bet. een the formulae corresponding to the 
second and third columns. This formula is 15Mn203.4MnSi03, the ratio 
between Mn203 and MnSiOs being .3,| : 1 instead of either 3| : 1 or 4: 1. 
The Kacharwahi specimen, on the other hand, corresponds very 
closely to the formula 7Mn203.2MnSi03, the chief points to notice, 
in comparing the figures given on page G9 with those for the formulae 
given above, being the amounts of manganese, silica, and available 
oxygen, the amounts of the oxides of manganese being of less value in 
making this comparison because a small error in the determination of 
the available oxygen produces a considerable change in the ratios 
of the peroxide to protoxide of manganese. 
The figures, as given on page 69, deduced from the Kajlidongri 
analysis, correspond most closely with the formula in the first column 
above, namely to 3Mn203.MnSi03. The most noticeable deviation from 
the theoretical formula is in the ratio of the oxides to one another. 
This, however, corresponds to a relatively small error in the determina- 
tion of the available oxygen. 
From the consideration of the foregoing three analyses it appears 
