198 
MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ ParT I : 
condition. Owing to the interlamination of these two micas the 
determination of their pleochroism schemes is a matter of difficulty. 
2. The S Uapathur mica occurs in a rock composed of this and a bronze 
mica (page 197) with quartz, the whole rock as far as could be judged 
from the outcrop forming one wall of the manganese-ore deposit at this 
place. 
3. At Ghouara the mica occurs in some thin cracks ^ to — inch wide 
" 64 32 
traversing the nodules of manganese-ore that are foimd in the crystal- 
line limestone at this place. The colour of the mica is hght crimson. 
4. At Kdcharwdhi there are numerous layers of micaceous schist 
interbanded with the layers of manganese- ores and other manganifer- 
ous rocks forming the manganese-ore deposit. These micas vary in 
tint from specimen to specimen, some being pink, some brown and 
others of intermediate colour. ^Vhen they are examined it may be that 
some of them will be found to belong to aluxgite. 
The pleochroism schemes of these micas and their optic axial angles 
as determined by means an eye-piece micrometer and comparison with a 
flake of muscovite of known angle, are shown in the following table : — 
Table 18. 
Optical properties of pink micas. 
Locality. 
i 
Colour in 
hand-.speci- 
men. 
Optic axial 
angle. 
Pleochroism. 
a 
b 
C 
I. Kajlidon- 
gri- 
Crimson 
Crimson layers : 
Amethystine. 
Orange layers : 
Greenish yellow. 
Brownish pink 
to light rose. 
Pale green . 
Deep rose. 
Orange-red to 
deep orange. 
2. Sitapathur 
Rose red 
47°— 60° 
Pinkish lilac 
Light pinkish 
orange. 
Rose. 
3. Ghogara 
Rose-red or 
light crim- 
son. 
59°— 65° 
Lilac 
Yellowish pink 
Light rose t o 
lilac -rose. 
4. K a c h ar- 
wahi. 
5. Jothvad . 
*5 St. Marcel 
Piedmont 
(Alurgite). 
Pink 
Pale green 
Orange. 
Deep brown- 
ish copper 
red. 
.56°— 57" 
Red with a pur- 
plish cast. 
Brownish red 
Red with a pur- 
plish cast. 
