120 Brush and Dana—Fairfield County Minerals. 
The mineral lithiophilite is consequently a manganese mem- 
ber of the triphylite group. r. Penfield has previously 
shown that the true formula of triphylite, hitherto doubtful, is 
II 
R ;PO,+R,P,0,,* where ae Li, and R=Fe mostly, also Mn. 
His conclusions are confirmed by the results of Mr. Wells’ 
apalyele | of lithiophilite 
Rammelsberg eg (as a mean of four analyses) in the 
hodeniuata mineral 39°97 p. c. FeO, and 9°80 MnO. Mr. 
Penfield, in his analysis of the Grafton, Row Hampshire, 
obtained 26:09 p. ¢. of FeO and 18°17 p. c. ‘MnO. The altered 
triphylite from Norwich, Mass., also contains a considerable 
amount of manganese, but as manganese sesquioxide (22°59— 
24°70 p. c.); the unaltered mineral has never been analyzed. 
These facts go to show that between the true triphylite,—the 
tron-lithium phosphate—,and the lithiophilite,—the manganese- 
lithium phosphate—a number of different compounds exist, 
containing varying amounts of iron and manganese, as is true 
in many other analogous cases of isomorphous groups of com- 
pounds. It is proba able, however, that to all varieties of the 
two minerals belongs the hese formul 
RPO, +R,P,0,. 
Pyrognostics.—In the closed tube gives traces of moisture, 
turns dark-brown and fuses but does not become magnetic. 
Fuses in the naked lamp-flame and B. ives an intense 
lithia-red flame streaked with pale green on the lower edge. 
Dissolves in the fluxes giving in O.F. a dee prea ae bead, 
and in R.F. a faint reaction for iron. Soluble 
The name lithiophilite, from lithium and ihe, “Ripoik may 
properly be given to this species as it contains a very high per- 
centage of lithia. 
5. Reppryerre, 
Physical characters.—Reddingite occurs sparingly in minute 
octahedral crystals, belonging to the orthorhombic system. It is 
also found more generally massive with granular structure ; it 
is plage with dickinsonite, and sometimes with triploidite. 
compared with the other species which have been described 
‘ti is a decidedly rare mineral. The massive mineral shows a 
distinct cleavage in one plane, the crystallographic direction of 
pi could not be ascertained in the crystals owing to their 
s 
The Rani ess is 3-35; and the specific gravity for the min- 
eral analyzed, containing 12 p. c. quartz is 3°04; this gives on 
calculation for the pure mineral 8°102, The luster is vitreous 
to sub-resinous: the color of the perfectly unaltered mineral 
* This Journal, II, xiii, June, 1877. 
