GSG MANGANESE DEPOSITS OF INDIA : DESCKIPTIVE. [PaeT IV : 
ant in cross-cut 3 and the adjacent quarries. As has been previously 
indicated, it forms with psilomelane a group of complex manganates 
in which barium is a prominent constituent, and we see from this the 
reason why the ore deposit south of the waist is much higher in baryta 
than that north of the waist, where there is a much larger proportion of 
braunite to psilomelane and where hoUandite is absent. 
Winchite and Blanfordite. — The blue amphibole, winchite, which may 
be regarded as a variety of tremolite containing iron and small quantities 
of manganese and alkalies and having curious optical properties, occurs 
at the north end of the deposit in a band about 4 feet wide, conforming 
to the general strike of the deposit. The typical rock is composed of 
winchite, braunite, calcite, and quartz, and may be called a winchite- 
schist. But associated with this are bands of a very fine-grained white 
or pale grey quartzite containing abundance of lavender-coloured win- 
chite, often in beautiful simple prisms. In this rock are green spots, 
and sometimes green crystals, which consist of a pyroxene showing 
what I have designated as the blanfordite type of pleochroism (see page 
127). In quarry No. 2 a certain amoimc of winchite occurs in a pink- 
ish clayey rock immediately underlying the ore-body. The winchite 
is most abundant at the contact with the manganese-ore and rapidly 
diminishes in quantity, so that at 2 feet from the ore-body the rock 
becomes a sandy-argillaceous one without any winchite. 
Rhodonite. — This mineral occurs at the very north end of the deposit 
in a ridge just to the S.W. of the quartzite hill shown in the plan. 
All that I saw was much blackened owing to partial conversion into 
manganese-ore. In one place in this outcrop is a nodule of red quartzite 
roimded at one end and drawn out at the other. It is included in a rock 
composed of rhodonite, apatite, quartz, and yellow pyroxene, with some 
spessartite. This rock is partly altered to manganese-ore and curls 
round and envelops the quartzite in such a way as to suggest that the 
manganese-silicate-rock must have once been molten and have picked 
up the quartzite when in that condition.^ 
Spessartite. — This occurs as typical spessartite-quartz-rock (gondite), 
with abundant associated apatite, in the dyke-like outcrop running 
N. 10° W. towards the river from the west side of the quartzite hill 
at the north end of the deposit. This outcrop consists of grey, clove, 
and pink, quartzites, in which occur bands of spessartite-bearing rocks, 
in places much mixed up with vein-quartz. Some of these manganese- 
1 The occurrence i.s, however, regarded as a part of the gondite series — of sedimentary 
origin — see Chapter XV. 
