384 Scheerer on Isomorphism. 
cannot but look on this simpler expression as the true representa- 
tive of all cordierites. 
this however as it may, it noways influences the deduc-~ 
tions which, as will be seen below, we draw from the composi- 
tion of the mineral in question, and the other formula may, wi 
equal propriety, be looked upon as the correct one. It, neverthe- 
less, struck me that the agreement of the formula of cordierite 
with that of the closely allied hard fahlunite, was a point of suf- 
ficient interest to justify these passing remarks. 
Aspasiolite.—In most of its mineralogical characters, espe- 
cially in color, lustre, translucency and hardness, this substance, 
which occurs at the same locality as the cordierite just described, 
agrees very closely with serpentine.* It is usually of a green 
color of various shades, mostly light, such as leek-green, aspara- 
gu n, oil-green, &c. Here and there the mineral exhibits 
portions of a brown or reddish-brown color, which appears to 
oe etal E 
_* ZT received both substances from Messts. Dahl and Weibye of Kragerde, min- 
eralogical students at this University, to whose kindness [ am already indebted 
for several interesting minerals. 
