148 MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ ParT I t 
is often to | incli in diameter. In one specimen from Hatora, however, 
the amphibole occurs as rather conspicuous radiate white asbestiform 
needles often altering to a greenish black colour, on the parting planes 
of a fine-grained variety of gondite. In the Kandri example the rock is 
also fine-grained, the amphibole, the determination of which is somewhat 
doubtful, being noticed only under the microscope. Usually the 
mineral is conspicuous in the hand-specimens, appearing as radiate 
or semi-radiate bundles or sheaths, usually with the fibres J to ^ or 
even 1 inch in length. When fresh the colour of these sheaths varies 
from greenish grey to brownish green and yellowish or buff. The fresh 
mineral is best seen in the specimens from Parsioni and Chikmara (col- 
lected by Mr. C. M. P. Wright). When in this fibrous condition the lustre 
of the mineral is silky. But sometimes the width of the individual fibres of 
the aggregate is greater and then the mineral tends to be bladed in appear- 
ance. Very frequently the mineral is partly altered, the colour then 
being usually some shade of chocolate, whilst the mineral is softer than 
when fresh. Under the microscope this alteration is seen to take the 
form of a brownish powder deposited along both the cleavages and cross 
cracks of the mineral. Owing to the fibrous or thinly prismatic nature 
of the mineral it is vjry difficult to obtain good sections for microscopic 
examination, the fibres separating out long before the section is sufficiently 
thin. Nevertheless, several prismatic sections have been obtained ; 
but it is almost impossible to obtain a cross section showing the 
cleavages characteristic of amphibole. In one specimen from Bichua, 
however, such a section was obtained exhibiting the cross-cleavages 
of the amphibole group and thus confirming the deduction as to the 
nature of this mineral. The prismatic sections show extinctions (c c) 
up to 22°, the highest value in several examples approximating to this 
figure. The birefringence is low, the polarization colours being of the 
first to second order. In some cases the mineral is practically colourless 
as seen under the microscope ; but in others it shows pale colours, then 
being slightly pleochroic. Thus a sHde of the Hatora occurrence shows : — 
=very pale brownish yellotv, 
tj = slightly darker brownish yellow ; 
whilst one from Bichua shows a pleochroism of pale greenish brown to 
colourless. 
From their mode of occurrence and general appearance it seems 
probable that all the above occurrences are of the same mineral, except 
that of Pali, which is in a piedmontite-gneiss. This amphibole is yellow- 
