52 
THE CONSTITUTION OF THE SILICATES. 
[BULL. 125. 
On the latter basis it agrees in composition with a hydrated manga- 
nese phlogopite, having the subjoined admixture of molecules: 
1. Al(Si 3 8 )3Mn 3 H3.2aq. 
1. Al(Si0 4 )3Mii3H 3 .2aq. 
2. Al(Si0 4 ) 3 Mn 3 KH 2 .2aq. 
3. Al(Si0 4 ) 3 Mn 3 NaH 2 .2aq. 
or, in percentages, as follows : 
Found. 
Si0 2 .. 
ALU, 
Fe,0 ; 
MnO 
CaO. 
Mg(.) 
PbO 
KoO. 
Na,0 
H 2 0. 
Calculated. 
39.67 
39.99 
7.95 
I 
8.81 
.90 
35.15 
1 
36.80 
1.11 
1 
.20 
.20 
2.70 
2.33 
2.18 
2.29 
9.79 
9.78 
99. 85 
100. 00 
Of this water G.22 per cent is crystalline and 3.56 constitutional. 
The associated manganophyll has also phlogopite ratios, but varies 
so widely in composition as to show that it is, like many other micas, 
a mixture. Hamberg gives two analyses of this mineral; the first 
variety, of a reddish-brown color, agrees with 
,Si0 4 =MnK .Si0 4 =MgK 
Fe-Si0 4 =MnH + 4Al-Si0 4 =MgH 
^Si0 4 =MnH ^SiO.EEMgH 
The second variety, which is dark-brown, may be written 
,Si0 4 =MnK .Si0 4 =MgK 
+ 4Al-Si0 4 =MnH + 5Al-Si0 4 =MgH 
\si0 4 =MnH \si0 4 =MgH 
3Al-0/ M S 
^iO^Fe'" 
These manganophylls are from Pajsberg, but the manganophyll from 
Longban, analyzed by Flink, has ratios which indicate the presence of 
biotitic molecules somewhat similar to those found in alurgite. Man- 
ganophyll, however, contains among its constituents a true manganese 
phlogopite, of which ganophyllite is most probably the hydrate. On 
this basis both minerals are most easily explained, and all their rela- 
tions are accounted for. 
Between the micas and the chlorites the relations are exceedingly 
close, as regards both composition and physical properties, and from 
certain points of view the vermiculites are to be regarded as a transi- 
tional series connecting the two groups. All the species are highly 
