278 Brush and Dana—the Spodumene of Branchville, Conn., 
Occurrence of Killinite and Cymatolite—In many of the massive 
specimens, the spodumene is changed in part to killinite and in 
art to eyanntellte, the two minerals being intimatel waa’ 
ated with each other. This association is illustrated : 
in which ¢ is the fibrous cymatolite and & the killinite. "ng 
latter makes up the mass of the specimen, and the oe 
with its usual transverse fibrous structure, is in thin ban 
following nearly the original cleavage lines 
It is the confusedly massive variety of the spodumene which 
has furnished nearly all of the killinite. In the distinct crystals 
it rarely appears, though here it is sometimes seen, as indicated 
by fig. 12, as a more or less irregular surface covering. 
UL. GENETIC RELATION pecitione THE ORIGINAL SPODUMENE AND THE VARIOUS 
PRODUCTS OF ITS ALTERATION 
The general character of the process of alteration, by which 
the spodumene was changed into the various products already 
described, was, in a word, as follows :—it consisted essentially 
in the substitution of sodium and potassium for the original 
alkali lithium. The interesting facts, that have been detailed, 
in regard to the compound nature of the substances called 
8 spodumene and cymatolite, taken in connection with the 
whole process tolerably clear and simple. The fact that two 
bow one molecule of muscovite and one of albite, was clearly 
rought out by Mr. Julien; and he uses it to explain the 
mens from Branchville enables us to extend an complete this 
ag, 2 eR 
he relations of the various minerals involved in the change 
are presented in the following table, showing what may 
derived from the spodumene, assuming the change in alkalies 
to take place. 
2 ae Sy = [Li,Al,Si,0, + NazAl,Sics0i6], B Spodumene. (1) 
podumene. Eucryptite. Albite. 
= [(K, H),AlsSi,0. + NarAlsSioOse) Cymatolite. (2) 
Muscovite. 
ee aor ta be } NieALSiOy Ab 6 Microcline. (3) 
— first step in the process of alteration was the formation 
he # spodumene, by the substitution of sodium for one-half 
= lithium and the breaking up of the original spodumene, so 
as to form equal parts pute of albite and the new mineral 
which we have call cryptite. The true nature of this sec- 
ond mineral has rereny om been detailed. It would seem to be a 
