218 
MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ ParT I 
On grinding the sample for analysis it was found that a little free 
quartz was present. Consequently the analysis can be recalculated as 
follows : — 
Kaolin 93-42 
Qaartz 6-40 
.Surplus alumina .... 0-06 ' : 
99-88 
It is an interesting fact that many of the Indian manganese-ores when 
^ analyoed are foimd to contain AsoO^, though usually 
in exceedingly small quantities. Thus the highest 
amount returned in the analyses carried out at the Imperial Institute is, 
with one exception,. 0"022%, and in the analyses made by Messrs. J. & 
H. S. Pattinson, 0-047%. Nevertheless, it is an important point to 
determine the form in which this constituent is present in the 
ore. 
At two different localities I have found crystalline arsenates. One 
^.^ , ^ occurrence is at the Sitapar deposit in the 
^ < e a e. Qj^j^^^j^^j.^^ district, where the arsenate occurs as a 
pale pinkish white to white mineral mixed up with the manganese-ores. 
It is usually interstitial with regard to the other minerals present, 
and is translucent, with a greasy lustre, a rather even fracture, 
and a white streak. H.=5 in fresh pieces, for the mineral tends to become 
opaque white and softer. It is brittle and easily crushed and is soluble in 
dilute acids. Qualitative examination of the mineral shows that it is 
essentially an arsenate and phosphate of calcium with .small quantities 
of other constituents. As one specimen of the ore contained a piece of 
this mineral showing three sides of what looked like a hexagonal prism, 
it is possible that this mineral is isomorphous with apatite. This 
prismatic crystal shows thin white lines parallel to the basal plane, due 
perhaps to parting planes. Under the microscope the mineral is 
allotriomorphic with regard to the manganese-ores, shows a very high 
refractive index, and polarizes in greys of the first order. In one section 
two sets of cleavages at right angles were seen. These possibly corre- 
spond to basal and prismatic cleavages. Samples 10 and lOA, of which 
the analyses are given on page 787, of the ores of this deposit contained 
0 003 and 0 095 per cent. AS2O5, respectively, the original sample 
having been di\'ided into two, one free from visible arsenate and the 
other containing it. 
