44 MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ PaRT I : 
The two analyses are given side by side below :— 
Specimen Nu. 1080. Specimen No. A. 346. 
(Beldongri.) (Garividi.) 
Manganese peroxide (MnOa) . 23-67 24-94 
Manganese protoxide (MnO) . 38-24 38*53 
Ferric oxide (Fe203) . . . 28-85 31-29 
Alumina (AI2O3) . . . r32 2-10 
Barvta(BaO) . . . TSO 0-03 
Lime;CaO) . . . . r53 0-90 
Magnesia (MgO) . . . 0-99 1-20 
Potash (K2O) 0-06 
Soda (Na20) 0-14 
Combined silica (Si02) . . 0-91 0*20 
Free silica (Si02) . . .0-80 Nil 
Sulphur 0-03 
Phosphoric oxide (P2O5) . . 1 -07 0-03 
Arsenic oxide (AS2O5) . . 0-01 Nil 
Cobaltous oxide (CoO) .... 0-05 
Nickelous oxide (NiO) . ... Nil 
Cupric oxide (CuO) 0-03 
Lead oxide (PbO) NU 
Zinc oxide (ZnO) Nil 
Titanic oxide (Ti02) 0-14 
Cldorine and fluorine .... Nil 
Combined water . . . r32 0-30 
Moisture at 100°C . . .0-18 0 20 
Carbon dioxide (CO2) . . . O'OO Nil 
100-34 100-17 
Manganese . . . .44-02 45-02 
Iron 20-19 21-90 
Silica (total) . . . .1-77 0-20 
Phosphorus . . . .0-47 0-02 
Specific gravity . . . . 4"74 4*84 
It is evident from the foregoing analyses that these two specimens 
represent one and the same mineral composed practically entirely of oxides 
of manganese and iron ; all the other constituents being present in 
insignificant proportions may be regarded as impurities. The question is 
then to calculate from these two analyses the formula of the mineral. 
I will first consider the mineralogical composition of the Beldongri 
specimen. If the combined silica shown in the analysis be really in this 
