Chap. III. ] 
PYROLUSITE. 
79 
loses its hardness (4) and the resultant pyrolusite is probably only an 
aggregate possessing the outward shape of the manganite, but having 
the hardness characteristic of pyrolusite, namely 2 to 2 "5, this mineral 
being very soft and soiling the fingers. Its specific gravity is given as 
4"73-4"86. In colour the mineral varies from black to steel-grey and 
bluish-grey with a black streak. The lustre of the mineral is metaUic. 
In India this mineral is found at a large number of localities, at some 
of them in considerable quantities. In Mallet's Mineralogy of India, 
pages 57 to 59, an account is given of the various occurrences of this 
mineral discovered up to the time that work was written, (1887). 
I do not propose to notice in this place all ' the occurrences of this 
mineral in India ; for it would be very tedious and take up a large amount 
of space ; the more important of them must suffice. References to 
this mineral will also be found throughout the descriptive part of this 
Memoir, and a reference to them can be obtained from the index. 
It is a pretty common mineral in the manganese-ore deposits of the 
^ Vizagapatam district, that is in those derived from 
the rocks of the kodurite series. Here it occurs 
more or less massive as a bluish-black ore of fine grain. This ore often 
exhibits little cavities lined with silvery black mammillations of the 
same mineral. An analysis of a picked specimen of this ore is given 
in the table on page 82. Sometimes the ore is found in sufficient 
quantities to be stacked separately from the other ores of the mine. This 
I saw being done at Kodur. In the mines of this area the pyrolusite 
seems to be most commonly formed by the replacement of the quartz- 
felspar-rccks accompanying the maiiganese-silicate-rocks, from which the 
replacing manganese is derived. A figure illustrating this method of 
formation is given on page 1085. 
In the manganese-ore deposits of the gondite series, that is those 
occurring in the Central Provinces and Jhabua, this mineral is the least 
common of the three common minerals of manganese, braimite, psilome- 
lane, and pyrolusite. In fact at a large proportion of the deposits it is 
not found at all, except perhaps as traces ; and of aU the deposits of this 
type the only one at which it occurs in any quantity is Kurmura or 
Ponwardongri in the Bhandara district, where there was a huge upstanding 
mass of ore composed of this mineral and psilomelane. The pyrolusite 
is line-grained soft and blackish (see page 752). 
At Pali, in the Nagpur district, there is an occurrence of very fine and 
pure pyrolusite in cavities in crystalline limestone, in which it has been 
