204 
MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ PaRT I : 
colmnbite or tantalite. When the amount of manganese present is 
very high the mineral is known as mangano-columbite, or mangano- 
tantahte, according to its composition. The amount of manganese 
protoxide, MnO, shown in the analyses quoted by Dana varies from 
0 81 to 13'88%. No analyses have yet been made of Indian specimens. 
The specific gravity ranges from 5'3 to 7"3. H. = 6. The colour is usually 
iron-black with a sub-metallic to sub-resinous lustre. 
This mineral has been found at four localities in India, two of them 
in the Monghyr and Hazaribagh district, Bengal, one in the Nellore 
district, and one in Mysore State. Probably in all cases, the mineral 
occurs in mica-bearing pegmatites. It was first found at the Dattu 
Mines, Pananoa Kill, near Nawadih, East Indian Railway, Monghyr 
district, by Mr. H. H. French, i the specimens sent being identified 
by Dr. T. H. Holland. The occurrence of the mineral was then 
examined by Dr. Holland who found that it occurs ' in lumps imbedded 
in the quartz of a very coarse grained pegmatite dyke, intruded into 
a mica schist, which is crowded with tourmaline crystals. 
The mineral was next found by the late Mr. A. M. Gow Smith in the 
Government forest of Koderma in the Hazaribagh district, Bengal. 3 
The specimens from this locality were found to have a considerably 
higher specific gravity than those from Nawadih, namely 6' 19, as against 
5-54. 
The third find was by Dr. T. L. Walker in the mica-bearing pegmatite 
of Chaganam, Nellore district, Madras, the specific gravity of the 
mineral being 5"75.4 
The mineral has also been found by B. Jayaram who writes 5 — 
' .About 100 yards from the tank bund and 3| furlongs north of Masti occurs 
a vein of pegmatite traversing the hornbk^nde granitoid gn 'iss. It is si igulirly 
rich in a dark mineral probably columbite This black mineral has been 
observed in a few places altering into b'otite '. 
Masti is in the Bangalore district, Mysore, 
Judging from the specific gravities given above the mineral trom 
each of the three first localities contains more Nb205 than Ta^Og, 
and is therefore to be called columbite rather than tantalite. The value 
of columbite and tantahte depends rather on the percentage of tanta- 
lum than on that of the niobium present. Judging from the specific gravity 
1 Ktc. Geol. Surv. Ind., XXVII, p. I at end of volume, (1894). 
2 Rec. Geol. Surv. Ind., XXVIII. p. 10, (189.5). 
3 Bee. Geol. Surv. Ird., XXX, p. 129, (1897). 
4 General Report of the Geological Survey of India for 1898-99, p. 9; ibid., 1899-1900, 
p. 9. 
5 Rec. Mysore Geel. D&pt., Ill, p. 182, (1900-01). 
