1142 General Notes. 
A mean of five closely accordant analyses gave: 
Fl SiO; TiO, CeO LaO DIO YO FeO Cad Na,O 
Ra SEE pts i aa % 
5-22 29.08 13.36 31.25 0.92 0.44 23.26 8098 = int 
The formula as deduced is : $ 
mav : 
2 RRO, 4+ NaFl 
II 
wherein R = Ce La Di Y Fe Ca 
and R = Si Ti 
Before the blowpipe it is fusible with difficulty to a black cin- 
der. It dissolves in borax in the oxidizing flame to a bead which 
is deep yellow when hot, pale yellow when cold. In the reducing 
flame it becomes colorless when cold. In salt of phosphorus 1t 
shows a skeleton of silica, and gives the same reaction when hot 
as with borax ; when cold, after heating in the reducing flame, it 
becomes violet. Supersaturation of the bead makes it opaque 
white. These reactions are due to titanium and cerium. its” 
decomposed by weak acids, with separation of silica and titanic 
acid, | 
The crystals exhibit in polarized light a twinning pang 
allel to the orthopinacoid. This structure is also shown by 
occurrence of fine striations on the orthodomes and aon ep 
Polylithionite' (Lorenzen).—At the same locality a pare | 
occurs in handsome pale green or white six-sided tables! isa. 
in albite. These tables are divided into sectors by pS plane , 
striations resembling those of zinnwaldite (lepidolite). pi e 
of the optic axes is at right angles to the striations, an The E 
crystals to be composed of three or six individuals. aa 
between the bisectrix and the vertical to the base is call their 
greater than that given for zinnwaldite, although practi a ‘he two 
optical properties are identical. The other characters : 
micas are very similar, cennet 
Chemically: the mica from Greenland has a larger per ‘ 
fluorine and of lithia and less alumina than most lepidouts 
A mean of three analyses gave: 
Fl SiO AIO FeO KO Mô He 
PSP as -isor “003 s37 7063 W of lithiè 
The name polylithionite refers to its large per oen an 
The mineral, however, is not sufficiently distinct pira soard. 
to warrant giving it a specific name, and shoul ee 
merely as a variety of that mica. Mins 
ik 
; ol 
| Goyazite* (Damour).—In the diamond-bearing a 
seraes, Brazil, certain rounded, transparent grains 0 
| Zeitsch. fiir Kryst., 1864, 1X, p. 2 
+ fiir , P- 261, 
~ *Bull, Soc. Min, de France, 1884, vil, No. 6, p. 204. 
Z 
