116 
MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ ParT I 
It is interesting that the manganese oxides returned in the onginal 
analysis, after using 1"28% for the spessartite, should turn out to be so 
nearly in the proportions required for MnsOs, i.e. for Mn2MnOg, corres- 
ponding to psilomelane in which all the basic portion of the manganate is 
occupied by manganous manganese. If, now, we regard the BaO, CaO, 
and MgO, as impurities, and reduce the Mn305, Fe203, and H2O, to 
molecular proportions, the following is the result : — 
58 -50 
MnsOs =■ = "2554 = 6 x "0426 
229 
6-88 
FeoOs = = -0430 = I x -0430 
160 
6 16 
H2O = = '3422 = 8 X -0428 
18 
These proDortions work out so exactly that it seems probable that 
they '"orresDoud to the definite formula : — 
6Mn305 Fe203.8H20. 
1^0 analysis has been yet made of the apparently similar mineral 
occurring at Chargaon, so that it is not known if there is really a definite 
mineral corresponding to the above formula. In order, however, to dis- 
tinguish it, it will be well to give it a temporary name, and the best suited 
for the purpose is beldongrite, after the place where the mineral occurs. 
The mineral is, however, only to be regarded as a variety of psilomelane 
and is not easily to be distinguished from the lead-like varieties, such as 
the Avagudem specimen referred to above, except in its darker colour. 
It is to be understood that this is only a provisional name, which it may 
be necessary to discard in the future, if it be found that other specimens 
of apparently similar material do not correspond to this formula. The 
actual specimen is to bii regarded as a mixture of beldongrite (7r54%) 
with 17'72% of quartz and 3'70% of spessartite. 
Wad. 
According to Dana, in his System of Mineralogy, 6th edition, page 258, 
the term wad includes a niunber of mineral 
"* " substances, such as bog-manganese, asbohte, and 
lampadite, that are not to be r egarded as distinct mineral species, but 
rather ' as mixtures of varisua oxides, chiefly of manganese (Mn02 also 
MnO), cobalt, copper, with also iron, and ^rom 10 to 20 j,'. c. watci ' 
