Chap. V. ] 
JUDDITE. 
150 
Juddite. 
Associated with the blanfordite of Kacharwahi in the Nagpur dis- 
trict there is a manganiferous amphibole with a pleochroism analogous 
to that of the blanfordite with which it is associated ; but it is, if possible, 
still more beautiful. The tints seen in a microscope slide showing 
a considerable number of sections of this mineral consist of various 
shades of rose, carmine, lilac, purple, blue, green, orange, and orange- 
pink. These tints are often very delicate, and their great variety is 
doubtless due to the combination of the colours corresponding to the 
different axes in varying proportions in various sections. As crystals of 
the mineral have not yet been isolated, it is very difficult to say which 
particular sections show the unadulterated axis-colours. But I think 
the following is somewhere near the true pleochroism scheme : — 
a = carmine, 
b=blue with a lilac tinge, to pale green with a lilac tinge, 
c = orange or pinkish orange. 
It will be seen that the colours corresponding to the ^ and b axes are 
somewhat similar to those of winchite ; but the c axis colour is quite 
different. The extinction angle a a f seems to have a maximum of about 
30° in sections showing the a and b axis colours. 
Some of the sections showing carmine and shades of green are at 
right angles to an optic axis, and from the brushes, obtained in these 
sections it seems that the mineral is positive, so that c is the acute 
bisectrix. I did finding not succeed in a section accurately at right 
angles to this bisectrix, but one figure that approached this position 
seemed to show crossed dispersion, as one would expect if b = c. 
One section showing orange and green tints, and hence at right angles 
to the a axis, was apparently at right angles to the obtuse bisectrix, 
this also pointing to the positive character of the mineral. In 
a basal section showing the characteristic cross- cleavages of amphi 
oole, the colour corresponding to the long axis of the cleavage rhombs 
is pinkish orange to reddish orange (c), and that to the short axis is rich 
violet, the latter colour being compounded of the a and c axis col urs. 
It seems probable that the mineral is monoclinic and that the c axis 
coincides exactly with the b" crystallographic axis, and that the a and 
b axes lie in the plane of symmetry. But certain anomalies in the 
behaviour of the mineral suggest the possibility that the mineral may 
be triclinic approximating closely to monoclinic in the axial angles. 
This point cannot be settled at pre^'ent. 
