Reéramination of American Minerals. 211 
protoxyds. ‘This is rendered more obvious by comparing their 
oxygen ratios. 
1, Litchfield mica,.. ... .,.. 1: 
& Liebnerite, . . . 0, 'a: w.. 120882 OAS 
i eye. Sy pe 
4. Margarodite, . .°. . «. . 1:616: 8-95 
The striking similarity of these species would lead ns to sus- 
pect, that if new analyses were made of specimens from the 
original localities, they might prove identical. In all physical 
characters, except structure, there is a complete correspondence. 
their chemical constitution, owing to slight differences in the 
4, Unionite, identical with Oligoclase. 
This mineral was described by Prof. Silliman, Jr., in this Jour- 
nal; [2], viii, 384, The following are its characters. In general 
appearatice it resembles a soda spodumene. It has a very distinct 
cleavage in one direction. Lustre vitreous. Color white. d 
hess 6. Sp. Gr. 2-61. It is found with euphyllite at the corun- 
dum locality near Unionville, Pa. The results of three analyses 
are as follows: 
_ bi Al Fe C2 Mg © Na ; 
‘45 10-94 136 = 1-02==100°41 
: 6445 2097 = trace «= OTT.—“‘ikS= «dE S864 == 10009 
21-70 trace 0°85 0-49 — _ — «2102 
The third analysis, owing to an accident, is incomplete ; the 
“nstituents determined are given for comparison. _The oxygen 
sito of these analyses is very nearly 1:3:9, which gives. the 
formula ® $i+21 Sit, "his is the formula of oligoclase : the anal- 
Yses correspond with that species, and the physical characters 
being the same, there can be no doubt as to the identity of Un- 
‘onite and oligoclase, 
It is believed that this is the first time that oligoclase has been 
observed in the United States. 
5. Kerolite of Unionville, Pa., a hydrated silicate of Alumina. 
Associated with euphyllite and Unionite, there occurs a pe- 
iat amorphous mineral, which has been circulated among some 
Xaminations of the minerals from this locality, we thought it 
- Sufficient importance to ascertain its chemical composition. 
In physical characters it resembles Kerolite. Hardness 2-25. 
Sp. Gr. 2-92. Color yellowish white. Brittle. Crumbles to 
Pleces when thrown in water. Analysis gave: ; 
ie ; Naték Hf 
enanO ‘sen Fa ele trace —«-22°39==09°64 
