226 
MANGANESE DEPOSITS OF INDIA : MINERALOGY. [ ParT I 
With the resultant green colour, as explained above. The key is as 
follows : — 
Table 19. 
A key to fh" idetvtification of the black and dark grey iron, manganese, 
and chromium, minerals. 
Colour of Powder or Streak.l 
Hematite! 
r 
Red 
and sometimes 
ilmenite. 
Not red 
I 
Fu.-e with nitre and 
fusion mixture. 
H==5o— 65 
0=4-9— 5-3 
Hexasronal. 
No characteristic 
Colour. 
Test with 
magnet. 
Yellow colour. 
I 
Chromite. 
H=oo 
G=4-3— 46 
Cubic. 
Greeu colour* 
I 
Manganese 
minerals. 
r 
Strongly 
magnetic 
I 
Magnetite. 
H=oo— 6-5 
G=516— 518 
Cubic. 
Weakly or 
noil -magnetic. 
r : 
Apply fusioE and 
tin foil test for 
titanium. 
i 
Violet colour. 
I 
Ilmenite. 
H=5— 6. 
G=4-5— 5 
Hexas;ODal. 
Make microcos- 
mic bead. 
I 
Opalescent yeUow- 
greeu colou r for 
uranium. 
I 
Pitchblende 
H=5-5 
G=90— 9-7 
Cubic. 
I have given the hardness (H), specific gravity (G), and crystaDine 
system of each mineral. These characters should be determined as far as 
possible in order to confirm the identification of the mineral from this key. 
If the mineral reacts for manganese then recourse should be had to the 
following key, which is for the identification of the black and dark 
grey metallic manganese minerals found in India, together with a few 
not yet found in India, the possible existence of which it is necessary 
to consider. 
1 Limonile is sometimes extcrnall}' black and in<immillated so that .t resembles the 
manganese-ore psilomelane. It is, however, distinguished by its ycllow-hrowii st reak 
andabsence of reaction for manganese. 
