22 
Records of the Geological Survey of India. 
[vol. v. 
lustre on cleavage surface pearly, on lateral faces vitreous; color emerald-green and 
sensibly monochroic. The color is the same whether the light passes perpendicularly or 
parallel to the cleavage faces. Transparent in plates of moderate thickness. Biaxial; 
yields water in a glass tube. In platinum forceps emits a starry light, loses its color, and 
falls on the edges. 
The tourmaline associated with the above is jet black with rather brilliant lateral faces, 
and often has a columnar structure parallel to the direction of the seam. Diaspore has also 
been observed, but as yet in too small a quantity to admit of description. 
Euphyllite and tourmaline occur also in the jade bed d, the former as a scaly aggregate 
and the latter in a massive form. Microscopic crystals with metallic lustre and red color are 
observable, which appear to be white, but they are too minute to admit of chemical examin¬ 
ation. 
If I should revisit the Sone Valley next season, I hope to be able to furnish fuller 
information respecting this very interesting as well as valuable bed of corundum and to trace 
its outcrop east and west from present workings. 
Just north of Korchee (close to the Paigun nuddee, to the east of G o n d a Hill) 
Magnetite there is a bed of magnetite in the gneiss with a high southerly 
dip. It is a banded rock composed of alternate arenaceous 
and ferruginous layers, the latter being granular magnetite. The layers are probably due 
to beddiug, for in a nulla near this, the sand, which is derived from this rock, exhibits a 
similar alternation of silicious and magnetic sand. 
The rock, which is friable, is pounded up into coarse powder and smelted near Korchee, 
being afterwards worked up into Kolharis, Ac, As the powder consists entirely of magnetic 
and silicious grains, it might be very advantageously washed in the P a n g u n nuddee, by 
which process the latter could be easily and rapidly removed and the yield of iron con¬ 
siderably increased. As usual with the natives no dux is used, so that the elimination of 
the silica would be an important gain. 
Hornblende rock is very abundant in some parts of the gneiss, often rising into hills on 
Hornblende rock, tremolite rock, account of its groat hardness. Very often, however, it does 
and jade. not g0j aiM j man y 0 f largest hills are of granitic 
gneiss. Sometimes ( e . g., west of Dumrahur and Urjhut) instead of the usual dark-green 
color, the hornblende is light-grey, and tremolite rock becomes the most appropriate term. 
The latter again passes into a light-grey or greenish granular to nearly compact hornblende or 
jade. Such is met with iu many places, more noticeably between Kotamowa and Bumnee, 
and the top of Kurea Ghat, where bands of a foot to a few feet in thickness are interbedded 
with mica schist, north-west of Ivisaree, where olive-green jade occurs, and associated with 
the corundum of Pipra. 
Accidental minerals are not numerous in the gneiss itself. Small crystals of magnetic 
iron are rarely scattered through the mass of the rock 
Accidental minerals m the gneiss. . . . , , , 
and llmemte sand nas been observed m one or two streams. 
Schorl is a not unfrequent mineral, and garnet is also to he found in places. It is worth 
noting that as far as my observation has gone, schorl is confined to the white felspar gneiss 
and garnet to it and to the hornblende schists, while epidote only occurs iu the red felspar 
gneiss. Pieces of red stilbite have been found in streams, but have never been observed 
in situ. As, however, there is no trap in the district except some doubtful dykes, it is most 
probable that the stilbite occurs as a secondary mineral in the gneiss itself as a lining of 
fissures or otherwise. 
