960 
MANGANESE DEPOSITS OF INDIA : DESCRIPTIVE. [PaRT IV : 
Specimen No. 932. — contd. Per cent. 
Phosphoric oxide (P2O5) . . . . . . .0-01 
Arsenic oxide (AS2O5) ....... 0-012 
Combined water (H2O) ....... 1-40 
Moisture at 100°C 0-12 
Carbon dioxide {CO2) . . . . . . .0-09 
99-922 
This is equivalent to : — 
Manganese . . . . . . . . .60-79 
Iron 0-04 
Silica 0-33 
Phosphorus 0-004 
Moisture 0-12 
Specific gravity . . . . . . . . .4-88 
The ore is, however, not always pure, but is often mixed with crys. 
tallized quartz ; and sometimes the rock takes the form of quartz con. 
taining spherical aggregations of pyrolusite. The pyrolusite is also 
often extremely fine-grained, so as to be almost amorphous. A sample 
of pjTolusite weighing 28fb was broken from in situ. It consisted 
mostly of the botryoidal-radiate ore with compact pyrolusite between. 
Some pieces contained a little chalcedony. An analysis made at the 
Imperial Institute showed the following :— 
Sampk No. 16. Per cent. 
Manganese peroxide ........ 72-71 
Mangane.se protoxide ........ 2-98 
Ferric oxide 2-98 
Combined silica ........ 5-31 
Free silica . . . . . . . . .13-17 
Phosplioric oxide . . . . . . . . 0'13 
Moisture at 100°C 0-43 
Carbon dioxide . . . . . . . . .0-15 
This is equivalent to : — 
Manganese 48-33 
Iron 2-09 
Silica 18-48 
Phosphorus ......... 0-06 
Moisture 0-43 
Owing to the miode of occurrence of the ore it will be seen that it could 
not, even if the average manganese contents were very high, pay to 
extract it for use as a source of manganese in the manufacture of ferro- 
manganese, owing to the great expense that would be incurred in blasting 
the limestone. Both physically and chemically, however, the average 
ore is not suited for this purpose ; but owing to its high percentage of 
manganese peroxide (Mn02), 72 "7 per cent, in the above sample, it is well 
suited for the manufacture of chlorine. Picked pieces, similar to that 
of which the complete analysis is given above, would, on account of 
the remarkably low percentage of iron, be especially suited for use in 
the manufacture of glass. Just before the time of my visit, some 25 to 30 
