DeEC;,, 1908. MINERALOGICAL NOTES 159 
large and small calcite crystals. The color of the realgar in both 
specimens is a superb carmine-red. The crystals are transparent. 
The habit of the crystals in the specimen numbered M 8204 is, as is 
usual with realgar, short-prismatic. These crystals are highly modi- 
fied and doubly terminated. A marked feature is the large number 
of prisms present, no less than nine being observed. The planes are 
remarkably brilliant and afford excellent signals on the reflecting 
goniometer. The prisms are often scarcely more than lines, but 
nevertheless give well-defined signals with the goniometer. In some 
of the crystals the basal plane is quite prominent, while in others 
pyramids and clinodomes are extensively developed. The clinopina- 
coid may also be quite fully developed. The two most prominent 
types exhibited by these crystals are shown in Figs. 1 and 2, Pl. 
LIV. As there represented, a slight elongation in the direction of 
the clino-axis usually occurs. The crystals average about 4 mm. in 
length. . 
The specimen numbered M 8205 is from the Golden Gate mine. 
In habit the crystals of this specimen seem to be different from any 
hitherto noted in realgar in that the prism is elongated in the direction 
of the vertical axis. None of these crystals is doubly terminated. 
The terminations on the single terminated end are simple as com- 
pared with those of the crystals previously described and there is no 
large number of prisms present. The prismatic development here is 
produced chiefly by the prisms m (110) and/7 (210). Like the crystals 
previously described these crystals also show a slight elongation in 
the direction of the clino-axis. The average length in this direction 
is about 7 millimeters. In the direction of the vertical axis a length 
of 15 millimeters is frequently exhibited. Fig. 3, Pl. LIII, illustrates 
these crystals. Some of the smaller crystals of this specimen are 
hollow in the direction of their length. A basal projection of all the 
forms observed upon both specimens is given in Fig. 4, Pl. LIV. 
The following is a list of the forms observed, together with meas- 
ured and calculated angles: 
a (100) Seot2ot) v* (230) 
b (oro) h (610) p> (120) 
c (oor) L- (210) & '(250) 
q (ort) © 6 (320) ft - (ata) 
r (o12) w (430) e- irt) 
y (032) n (650) n (212) 
« (lor) m (110) 
