208 MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ PaRT I : 
3'404 to 3"409, or, say, 3'40 to 3'41. It fuses rather easily to a dark- 
brown mass, and is foand by qualitative analysis to be a phosphate of 
manganese, magnesium, and sodium, with a little calciiim, and possibly a 
little iron. Water is doubtfully present. The mineral is uniaxial and 
slightly dichroic. 
The uniaxial character of the mineral was determined by means of an 
interference figure obtained in a chance section. If true it is a most 
important character, because none of the manganesian phosphates are 
uniaxial except manganapatite, which is quite different to this mineral in 
most respects. . Hence there seems to be no alternative to regarding this 
mineral as a new species. In case the determination of the uniaxial character 
of the mineral be at fault it is as well to see what minerals this phosphate 
is otherwise most closely related to. In specific gravity and hardness 
it agrees with natrophilite, an orthorhombic mineral of the formula 
NaMnP04. But it differs from the latter in containing magnesium in 
addition to the other constituents, and in being green in colour instead 
of wine-yellow, the colour given for natrophilite. It agrees with 
dickinsonite in colour, and fairly closely in specific gravity. It is, 
however, harder, and is practically free from iron, containing magnes- 
ium instead. These are the only phosphates to which the mineral seems 
to have any resemblance. Hence even if the two determination of the 
uniaxial character of the mineral be at fault it must still be regarded as 
a new mineral. I do not, however, propose to name it until its characters 
and chemical composition have been more fully ascertained. 
Wolfram, 
Wolfram or wolframite is a heavy dark brownish to black mineral 
^^^^ ^ ^ of monoclinic crystallization. H.-=5 to 5"5. G. =:7'2 
to 7"5. The streak is usually some shade of dark 
reddish brown to black. Perhaps one of the most characteristic features 
of this mineral is the perfect cleavage parallel to the plane b, so 
that the mineral looks as if it were laminated. In composition it is 
a tungstate of iron and manganese. When the latter is present to the 
exclusion of iron the mineral is called hiibnerite. 
In India wolfram has been found in the Hazaribagh district, 
Bengal, ^ and in several places in Burma. In 
Occurronce in India. ,i i , , i j -j. r . 
the latter area placer deposits oi tmstone are 
to be found in many of the streams and rivers draining down from 
1 Hec. Gcol. SurV. Ind., XXI, p. 21 (at end of volume ), (1888). 
