Chap. HI. ] 
VREDENBURGITE. 
45 
condition then it will probably be as braunite. On this assumption 
the analysis can be re-stated as follows : — 
Apatite 
2-47 
Calcite 
0-20 
Braunite 
9- 12 
Hausmannite 
53-82 
Hematite 
28-85 
Impurities — 
Alumina 
1-32 
Baryta 
1-30 
Lime 
0-02 
Magnesia 
0-99 
Combined water 
1-32 
Quartz 
0-86 
Arsenic oxide 
001 
Moisture 
0-18 
100-46 
Subtract oxygen assumed 
0-12 
100-34 
On the supposition that the combined silica is present as braunite 
there is no alternative to the above interpretation of the analysis ; for 
the jVIn304 and Fe203 are not then present in any simple molecular 
proportion. But in accordance with this interpretation there should 
be three constituents easily visible in the hand-specimen, namely brau- 
nite, hausmannite, and hematite. Examination of the specimen, however, 
does not reveal the presence of more than one constituent. If, on 
the other hand, we assume that the combined sUica is in combination 
with some of the impurities, then the analysis can be stated as follows : — 
Apatite 
2-47 
Calcite 
0-20 
ilnsOi 
61-93 
Fe203 
28-85 
Impurities 
5-86 
Quartz 
0-86 
AS2O5 
001 
Moisture 
0-18 
100-36 
Subtract oxygen a».suined 
0 02 
100-34 
