50 
MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ ParT 
values for this constant of 4:"93, 4*99, and 5*09, the mean value being 
5'00. An analysis of this mineral was made by Mr. T. R. Blyth, 
. , . . of the Geological Survey of India, on a piece having 
Cnenncal composition. . / rrn 
a specmc gravity oi -4 '93. Ihe result is as 
follows : — 
Specimen No. 843 A. 
Manganese peroxide 
Manganese protoxide 
Ferric oxide 
Alumina 
Baryta . 
Lime 
Magnesia 
Silica 
Moisture at 100° 0. 
Manganese . 
Iron 
Specific gravity 
36-79 
26- 89 
27- 60 
1-02 
0- 10 
6-14 
1- 02 
1-17 
0 09 
100-82 
44-09 
19-32 
4-93 
Below are compared the figures for the oxides of manganese and 
iron, and metallic manganese and iron, with those for the two specimens 
of vredenburgite of which the full analyses are given on page 44 : — 
Beldongri. 
Garividi. 
Sita 
par 
Mn02 
. 23 
67 
24 
94 
36 
79 
MnO 
. 38 
■24 
38 
53 
26 
89 
Fe203 
. 28 
85 
31 
29 
27 
60 
90 
76 
04 
76 
91 
28 
Mansranese . 
. 44 
62 
45 
62 
44 
09 
Iron . 
. 20 
19 
21 
90 
19 
32 
It will be seen that there is a striking resemblance between the Sitapar 
mineral and the two specimens of vredenburgite, particularly in the 
amounts of ferric oxide, manganese, and iron. The difference 
between the two minerals lies, however, in the state of oxidation of 
the manganese. Whilst vredenburgite contains considerably more MnO 
than Mn02, the relative amounts of these two oxides are reversed in the 
Sitapar mineral. Consequently the Sitapar mineral cannot be made 
to conform to the formula of vredenburgite. In the case of vreden- 
burgite I regarded the constituents other than the above as impurities, 
because none of them was present in any important quantity, nor had 
