Brush and Dana—Fairfield County Minerals. 363 
P.O; 39°30 
FeO 6: 
MnO 13°10 
CaO 30°99 
H,O 9°97 
The fact that the second variety was friable and somewhat 
deficient in luster suggested an incipient alteration, but the 
analysis did not confirm this idea. The larger amount of ae 
the ligeds proportion of iron may be due to the fact that this 
variety could not be entirely freed from the black oxide inter- 
penetrating it. 
Pyrognostics. —In the closed gat fairfieldite gives off neutral 
water, and the assay turns first yellow, then dark brown, and 
ecomes magnetic. In the forceps glows, blackens and fuses 
quietly at about 45 to a dark yellowish-brown mass, coloring 
the flame pale aren with faint ——. -yellow streaks on the 
upper edge. Soluble in the fluxes giving reactions for iron 
and manganese. Pairfioldite is aoltbts in nitric and hydro- 
Pairfieldite 3 is named from the county in which the locality 
curs. 
7. FILLOWITE. 
General physical characters. — Fi llowite occurs in granular 
crystalline masses. By fracture the crystalline grains can be 
usually separated with ease; they show in most cases merely 
Striated planes of contact, having no crystallographic signifi- 
cance; occasionally, however, isolated but brillant hie 
planes are observed and rarely a nearly complete cryst e 
masses are not infrequently penetrated by distinct priamatio 
crystals of tri loidite and sometimes they enclose particles of 
fairfieldite. The outer surfaces are very often coated with a 
silvery-white radiated mineral, but in so sparing quantities 
that we have been thus far unable to determine definitely 
its character. Reddingite is very commonly associated with 
fillowite, and in many cases it is not easy to iacarash the 
two mine 
he hardness is 45, and the specific gravity in two trials 
8-41 and 3:45. The luster is sub-resinous to greasy. e 
: eg generally Se also yellowish to reddish-brown 
n tinge, and nee almost colorless. Streak 
white Transparent to translucent; fracture uneven; brittle. 
ystalline form.—The RESON of fillowite, whose occurrence 
already been mentioned, have a marked rhombohedral 
