Chap. X. ] the identification op manganese minerals. 229 
Table 20. 
dark-grey, and bionze-coloured, manganese-ores. 
II. Scratched by a penknife. 
9. Pyrolusite 
. MnOz. 
10. Hausmannite , 
. Mn304. 
11. Manganite 
. Mn203.H20. 
12. Hollaudite . 
. niR"2Mn05 + n R"'4(Mn05)3; 
R"=Mn,Ba,Ca 
R"'=:Fe. 
8. P.^ilomelane . 
. mR"zMnOo + n R"'4(Mn05)3; 
R=Mn,Ba,K2, 
H2, etc., R"'=Fe,Mn,Al. 
13. Beldongrite . 
. 6Mc2MnO5.Fe2O3.8H2O. 
14. Wad. . 
. Indefinite mixture of oxides. 
r — 
Crystalline. 
1 
Non -crystalline. 
r 
Very soft. 
9. Pyrolusite 
G=4-73— 4-86 
Orthorhombic 
(prismatic). 
Fairly hard. 
r "1 
Octahedral Prismatic 
crystals and crystals and 
chestnut brownish 
streak, black to black 
I streak. 
r — 
Homogeneous 
and compact. 
10. Hausmannite. 
G=4-72— 4-86 
Tetragonal, 
Crystal.^ usually 
elongated. 
I 
II. Manganite. 
G=4-2— 4-4 
Oi'thorhombic, 
sometimes a 
bronze tarnish. 
Crystals usually 
stumpy. 
12. Hollandite. 
G=4-70— 4-95 
TricHnic ? 
r 
Dull. 
I 
S.Psilomelane. 
G=3-7— 4-7 
Mv.ssive and 
oncretionary. 
Very soft, often 
porous, black 
or brown. 
I 
14. Wad. 
Shiny; lead-like. 
I 
I 
13. Beldongrite. 
G=3-22 + 
Massive. 
