46 
MANGANESE DEPOSIT,? OF INDIA : MINERALOGY. [ PaRT I 
Now the Mn304 and Fe203 are present in the molecular proportions 
of 3 to 2 as shown below : — 
61-93 
=-2704 = 3 X 09013 
229 
28-85 
=-1803 = 2 X -09015 
IfiO 
Hence we can suppose that they form a mineral of the composition 
3Mn304.2Fe203, rather than a mixture of hausmannite and hematite. 
Taking now the case of the Garividi analysis, all the constituents 
may be regarded as impurities accidentally picked up during the 
formation of the mineral, except the oxides of manganese and iron, to 
which, as in the case of the Beldongri specimen, we will confine our 
attention. The oxides of manganese given in the analysis on page 44 
correspond to : — 
Manganese . . . .45-61 
Oxygon 17-86 
Now 45 '61 manganese requires 17*70 oxygen for the formation of 
Mn304, so that here also it seems almost certain that the manganese is 
present in the form of the proto-sesquioxide. Again the question arises 
as to whether this Mn304 is to be regarded as hausmannite in mecha- 
nical admixture with the Fe203 in the form of hematite, or whether 
the oxides of m.anganese and iron are in combination as some definite 
molecule with a definite molecular formula. Calculation shows that 
the relation between the Mn304 and the Fe203 is not so exact as in the 
case of the Beldongri specimen. Neglecting all the constituents 
except the oxides of manganese and iron the composition of the mineral 
is :— 
Mn304 . . . . 63-31 
FezOs 31-29 
Surplus oxygen . . .0-16 
94-70 
Now to satisfy the formula 3Mn304.2Fe203, (53 'SI Mn304 requires 
29*49 Fe203, whilst 31*29 is available; that is, there is a sur- 
plus of 1 * 80 Fe203. This is not excessive and may be taken as showing 
that the (Jarividi specimen has the same formula as the Beldongri 
