Ixviii MANGANESE DEPOSITS OF INT)IA. 
as due to the M112O3 group being probably a manganite with the 
following structural formula :— ■ 
0 
0 
fsomorphous with the structural formula of a metasilicate : — 
0 
/ 
0 
By the admixture in different proportions of molecules with different 
elements as R. all the varieties of braunite can be obtained, the only 
limits to the proportion in which these molecules may be mixed,, so that 
the mineral is still braunite, being that the ratio of RMnOs to RSiOs 
must not lie outside the limits i : 1 and 3:1, and that the number of 
molecules with Mn for R must be largely predominant. 
Mamjanite. — Several occurrences are known in India of minerals 
with the crystallographic form of manganite ; but none of them seem 
to be fresh. Some have been completely converted into pyrolusite, 
whilst some of them bridge the gap, as regards both chemical 
composition and physical properties, between pyrolusite and manganite. 
For these forms the name pseudomanganite is introduced. 
[CHAPTER IV.] 
Manganates and Carbonates. 
Hollandite. — The original notice of this new mineral is contained in 
the Iransactiotm of the Mining and Geological hvititute of India, Vol. I, 
