and the Results of its Alteration. 259 
larly. The angle of the prismatie cleavage—viz., 87° 13’— 
was obtained with great exactness. 
Chemical composition.—An analysis of the transparent pink 
spodumene was made by Mr. S. L. Penfield with the following 
results. Bea wiles 2a 198. 
Mean Ratio 
2 64 mn eo y 64°25 LOT: 
Al,Os 27°14 27°26 27°20 262 263 98 
FeO; 0-2 0-20 001 t 
Li,O 7°64 759 762 254 260 97 
Na,O 0°39 0°39 0°39 006 t 
20 tr tr tr 
Ignition 0°24 0°24 0°24 
99°91 99°88 99°90 
The ratio of Li,O: Al,O,: SiO, =1:1:4; this corresponds 
to the oxygen ratio* of 1:3:8. The formula is then, neg- 
lecting the very small amount of soda, 
Li,Al,Si,0.,. 
This result agrees exactly with that reached by Deelter in his 
investigation of the composition of spodumene,+ and with that 
of Julien.t It is to be noted, however, that the percentage of 
lithia here obtained is higher and that of soda lower than in 
any analyses previously published. For example, Deelter 
found in the storich mineral 7°04 Li,O, 1:10 Na,O and 0°12 
K,O; in that from Brazil 7:09 Li,O and 0:98 8 Na,O. Julien 
obtained in the Goshen n spodumene 6°89 Li,O, 0 99. Na,O, 1:45 
K,O; and in that from Chesterfield 6-99 Li 0, 0°50 Na. ‘0, and 
1°33 K O. Deelter concludes for the No rwich mineral that the 
B. ALTERATION OF SPODUMENE, 
As the result of the alteration of the spodumene, we have 
found two substances which at first sight seem to be homo- 
geneous, and each of which has a definite chemical composi- 
tion, and which, notwithstanding, are only intimate mechanical 
mixtures of two species; one of these, called by us § spodu- 
mene, is made up of albite and a new lithia mineral to which 
This ratio was obtained by bechonny from analyses of the Massachusetts mineral 
in 1850. Am. Jour. Sci., IT, x 
+ Tschermak, Min. u. Pe tr. Teitth, i, 517, 1878. t1L.c, p. 326. 
