266 Brush and Dana—the Spodumene of Branchville, Conn., 
in a cursory glance under a low power seem to be quite irreg- 
ular in form, are, on the contrary, A oereeapawe in parallel 
position. The solid portions are triangular or hexagonal in 
outline, and the bands are bent at angles of 60° and 120°, 
sometimes so as to form complete rings ;—they are all more or 
less rounded. In short, the structure is that of the most regu- 
tion in the albite of the new mineral in question. ey mar 
the mineral as belonging to the hexagonal system, and the 
result of the optical examination both parallel and transverse 
to the fibers confirms this conclusion. 
e ex: 
pected, the axial directions (60°) change at small distances, so 
that a given set of directions belongs only to a limited area; 
this is obviously determined by the enclosing albite. 
e are now able to connect the results of the microscopic 
by the fact that it, whenever distinctly separate, has the same 
structure as in undoubted cases of the same pseudomorphous 
material ; it is also shown by the examination of the insoluble 
portion alluded to before, for in this the fibers have been 
removed and the matrix left unattacked. The enclosed mine- 
ral is that which with the albite makes up the # spodumene, 
having the composition Li,A1,Si,O,. 
In view of the fact that this lithia-bearing mineral 1s thor- 
oughly defined, as well crystallographically as chemically, and 
considering, moreover, the important part it plays in the his- 
tory of the spodumene, we feel obliged to give it a distinctive 
name. Weceallit eucryptite, from ed well, and xpumrd¢ concealed. 
EvcryYPTire crystallizes in the hexagonal system, with proba- 
bly basal cleavage. Its specific gravity, calculated from that 
of # spodumene, 2°647 and that of the pseudomorphous 
albite 2°637, is 2°667. It gelatinizes with hydrochloric acid 
and fuses easily. It is a unisilicate, and its chemical compo- 
sition is expressed by the formula Li,Al,Si,O,=silica 47°61, 
alumina 40°61, lithia 11°88=100-00. Its mineralogical relations 
are not very certain; still, in form, and essentially in com- 
position, it is analogous to nephelite. It also might be viewed 
as a lithia-anorthite, it having the same ratio as anorthite ; 
though it is different crystallographically. On the other 
