ae 
ELISHA MITCHELL SCIENTIFIC SOCIETY. ral 
The mineral was analyzed by Dr. Chas. Baskerville* 
with the following results: | 
I ae 
Sp. Gr. Sp. Gr. 
2 °147-2°203 Ratio 2°203-2°244. Ratio 
mo, ..45°08 “751 3°79 46:15. “769 259-70 
Al,O, .19°68 -193 =k, OU 20°94 203 = 100 
FeO 2°00 = -028 | 2.00 :028 | 
CaO mee 7129" ) PE a he PR PS ea oe 
BaO AB OL PO. OR DRO ogy BAS ey 
MgO "23.005 ) 22? OOS) 
K,O 4°34 -064) .,. pi thirde.0.'2 043 4 
2 Ls hep e () = om e i Xe lo it tee eA 
a0 . 3:35 -0544 1°° oe BBS OBS Ha Te 
H,O ..18.00 1:000 — 5:02 16°30 .905 —- 4°46 
100°08 100°02 
The ratio of Al,O, : SiO,: H,O is near to 1:4:5 and 
Beeb ( WK, Na,)Ovis ,close to 4:5. 
Usually in the composition of the chabazites the ratio 
meni), : (Ca; kK... Na,)O is.near to-1 :,1. 
In the present 
analysis, no attempt was made to separate any strontium 
present from the calcium. As a small amount of this 
element would’ cause considerable variation in the per 
cent of CaO, this would readilv account for the excess of 
this oxide in the analysis. 
The composition of the chabazite has always been some- 
what uncertain as there 1s often a wide varation in the 
analyses of specimens from the same locality. The hy- 
pothesis advanced by Streng,?+ that the chabazite is an 
isomorphous mixture of 
{ m(CaNa,) Al,Si,O,+4H,O 
| 2(CaNa,)Al,S1,0,,+8H,0. 
explains satisfactorily the variations observed in this 
*Of the Chemical Laboratory, N. C. Geological Survey. 
+Ber. Oberhess. Ges. 16, 74, 1877 and Dana Mineralogy, sixth edi- 
eon, 1892, p. 591. ‘ 
