Chap. IV. ] 
BELDONGiKiTE. 
115 
Beldongiite. 
At Beldongri, on the north side of the pit, there is a variety of mangan- 
ese-ore, havin a smooth shiny fracture and the colour and lustre of 
pitch. It is somewhat like the specimen of psilomelane, A. 372, from 
Avagudem in the Vizagapatam district, of which an analysis is given on 
page 100 ; but is more shiny in its lustre, and darker. A piece of this 
picked for analysis contained a little spessartite-garnet, which, on account 
of its intimate association with the pitch-like mineral, could not be com- 
pletely removed. The latter in fact seems to have been derived from the 
garnet by some process of alteration. At Chargaon in the same district, 
a similar substance forms a matrix to the unaltered spessartite, from 
which it in this case also seems to have been derived by alteration. The 
specific gravity of the specimen chosen was 3"22, whiht its hardness was 4. 
The analysis, carried out at the Imperial Institute, is given on page 908. 
In calculating this analysis into terms of its mineralogical composition, 
there is no alternative, since no braunite is visible, to taking out the small 
quantity of combined silica as spessartite, assumed to have the formula 
3MnO.(Al,Fe)203.3Si02. It is found that the remainder of the oxides 
cannot be combined to make manganates owing to a great deficiency in 
the amount of oxygen required for this purpose. The free silica must, of 
course, be regarded as present in the form of quartz. This must, 
however, be in a very finely divided condition as it is in no way visible 
in the specimen. The analysis can then be written as follows : — 
Specimen No. 1079. 
Apatite . . 0'12 
Calcite 0 '25 
Spessartite 3 '70 
MnsOs 38-50 
re203 6-88 
BaO 0 78 
CaO 2-10 
MgO 0-15 
H2O (combined) 6 "16 
Quartz 17 72 
AS2O5 , 0-006 
Moisture 4 "21 
100 -575 
Subtract oxygen assumed .... 0 '82 
99 -755 
l2 
