88 
MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ PaRT I : 
to the composition of the typical hoUandite of Kajlidongri. Until 
more work has been done on these minerals I propose to use the name 
hollandite to include all the Indian crystalline manganates, though later 
on it may be foimd convenient to use the term in a more restricted 
sense. The other localities at which crystalline manganates occur 
are Gowari Warhona in the Chhindwara district ; Mandvi Bir, Jima- 
wani, and Junapani, in the Nagpur district ; and the Balaghat deposit 
in the district of that name : it is probable that crystalline mangan- 
ates will be found to be of much more common occurrence than would 
be suspected from the fact that up till now they have never been 
recorded as occurring in the natural condition. Wherever a specimen 
shows psilomelane passing into a crystalline mineral — such as is com- 
monly seen in the Sandur Hills and Mysore — one must be prepared for 
the possibility that the crystalline mineral may be hollandite, although 
as a rule it will probably be found to be pyrolusite or manganite. 
With the latter mineral in particular it is very liable to be confounded, 
especially when the manganite occurs in stumpy crystals. But, as will 
be seen from the account of the properties of hollandite given below, it 
is easy to distinguish the two minerals if pieces of any size can be 
obtained. The chief points of difference are the higher specific gravity 
and, when crystal faces can be used for the test, the superior 
hardness of the hollandite. A chemical test would also show that 
the mineral was hollandite if a strong reaction for barium were 
obtained ; but with regard to this latter test it must be noticed that 
although all the crystalline manganates hitherto found contain a con- 
siderable proportion of baryta, yet it does not follow that a crystalline 
manganate will not be found practically free from this constituent.^ 
It might also be thought that the presence of water of crystallization 
in manganite might be used as a criterion in distinguishing these 
two minerals. It must be remembered, however, that the Indian 
manganites are almost always in a state of partial dehydration owing to 
an incipient conversion into pyrolusite, with the result that they often 
give only a weak reaction for water when heated in a closed tube ; whilst 
the crj^stalline manganates, like the amorphous ones grouped under the 
term psilomelane, may contain water in the form of hydrogen in the 
base portion of the mineral. As an example of the confusion that 
may arise between these two minerals, I may mention that many 
of the Shimoga manganese-ores contain pseudo-manganite as a lining 
1 Such as a crystalline form of the American fibrous luad-munganctie manganate 
eoronadite (see page 96). 
