1034 
MANGANESE DEPOSITS OF INDIA : DESCRIPTIVE. [ ParT IV 
1. Boirani. 
This deposit is situated perhaps ^ mile S. 40° E. from Boirani village 
in some very slightly elevated ground, nearly barren of vegetation and 
surrounded by rice fields on the lower ground. It was discovered by 
Mr. T. Chaudry in June 1902, the surface indications being abundance 
of small granules and nodules of psilomelane lying on the groimd, 
as well as black stains and impregnations in some garnet-felspar-rock 
cropping out there. 
The source of all the manganese here is probably the manganese- 
garnet of a band of the rock I have called kodurite (see page 255), 
which when fresh consists of manganese -garnet, orthoclase, and 
apatite. The garnet is a manganiferous one intermediate in compo- 
sition between grossularite and andradite, and has been called grandite, 
(seepage 165). The felspar is white and the garnet occurs in abundance 
as small scattered and aggregated crystals of yellow and orange colour. 
Somewhat extensive excavations in the form of irregular pits have 
shown that this rock has a strike varying between E. 30' N. and 
N. 30" E. and that it is at least 21 feet wide, having a dip to the N. W. 
side of 35° to 50°. Almost everywhere the kodurite is greatly altered, 
the change taking the form of the replacement of the felspar by 
chalcedony and opal of various shades of white, black, brown and green, 
while the garnet may also be completely removed, or may remain as 
fresh crystals set in an opal-chalcedony matrix (see fig. 2, Plate 8). 
In other places the rock has yielded a soft bright yellow-green material. 
For an analysis of the Boirani kodurite see page 257. The rock im- 
mediately underlying the kodurite band seems to have been originally 
felspar -rock, with quartzite beneath this. The felspar-rock has been 
very largely replaced by manganese in the form of psilomelane, so as 
to form in one place an ore-bed of 4^ feet thickness. This bed was 
followed to a depth of 35 feet by means of a drive on the dip, and, 
judging from information supplied by Mr. Chaudry, the section must 
have been somewhat as follows : — 
Above: — Silici(ied and decomposed kodurite. 
G'' Decomposed felspar-rock with nodules and strings of psilomelane. 
2' Cavernous psilomelane, with the cavities filled with a siiiceous limonite, pro- 
bably representing the remains of original felspar-rock or gnei.ss, and 
still retaining some felspar. 
