64  Seheerer on Isomorphism. 
. Chlorite mineral, from Taberg. (Svanberg.)* 
Yess 1 609 : 16-98 Ase 
18:50 : 6-16 ; 16- as a(R)? Si+(R)> Al, 
which formula may likewise be thus given, 3Mg? Si+(R)? Al. 
The mineral contains 29-27 Mg, 2:07 K, 6:34 Fe, 1-64 Mn, 
11-76 H, and these bases are present in such ‘proportions as will 
admit of the entire magnesia and potash being combined with 
the silica, while the whole of the other weaker bases may be sup- 
posed to be in combination with the alumina. Hitherto, this 
mineral, notwithstanding its great external resemblance to chlo- 
rite, was reckoned among the micas, because the quantity of the 
1: 1 atomic bases which it contains (not counting the water 
therewith), is not sufficient for a member of the chlorite fan : 
now however, by including the water among the basic cons 
ys the mineral in fact takes its place among the chlorite group. 
, 8. Kémmererite.  (Hartwall.) 
19-20 ; 6:90 : 16°83 2 ee 
19:50 ! 650 : 16-25 6(R), Si+(R)? Al 
Pyrosclerite (v. Kobell) appears to have the same formula, un- 
less indeed the loss of 1°9 per cent. in the analysis should cause 
an alteration therein. 
9. Chloritoid. (v. Bonsdorf.) 
14:28 : 16:61 : 9:95 ok ae pe 
15:00 : 15-00 : 10-00§ ns Seri Sih ee pat 
The analysis gave an excess of 1:64. (R)=27:05 Fe, 429 
Mg, 0°30. Mn, 6-95 H. A. Erdmann has examined another chlo- 
ritoid which contains no water, and which (as the mean of two 
analyses ) ee the following oxygen ratio. 
2°95 : 21-02: 
6:8) 
13-06 1469. 50 : Gent 2(R)Si+R Als, 
this therefore, as has been remarked by Rammelsberg, i is evident- 
2 hh another mineral. ; 
10. Soapstone. (Svanberg.) 
24:32 : 3-87 : 16:39 Se edi spate ane 
23-40 : 3-90 ; 16-90% » G(R)? Si+(R)R. 
(R)=33:3 Mg, 0-7 Ga, 11- 0 H; R=8-0 Al, 0-4 Fe, 
bf Oronstedite 
The formula of this mineral, according to v. Kobell, is 
phe ss } 
Mn* Si+PeH , 
Mg?) 
* See Berzelius’s Jahresbericht, Jahrg. 20, Part 23 p- 234, f 
