1903. ] WRIGHT—CRYSTALLOGRAPHIC PROPERTIES. 247 
crystal habit are illustrated in Figs. 6 and 7 (dimensions of crystals 
0.9 X 0.9 X 0.4mm. and 1x0.5 X 0.4 mm.). 
The external appearance of the artificial argentodomeykite resem- 
bles that of domeykite. Its color is perhaps more nearly silver- 
white. The crystals tarnish easily and become iridescent. 
STIBIODOMEYKITE. 
The artificial products of this mineral were not suitable for gonio- 
metric measurement. The faces were without exception uneven. 
An examination of the various preparations with a pocket lens 
revealed two different types of crystal habit—the first of them tabu- 
lar with the base predominating, the other faces practically unde- 
veloped ; the second long prismatic, almost arrow-shaped, the hori- 
zontally striated pyramid faces terminating either in a short point 
or becoming wider at the top, and resembling then an overturned 
bottle or inverted cone. 
Color, light steel-gray. Tarnishes less readily than preceding 
minerals and iridescence rarely noticeable. Fracture conchoidal. 
H = 3-4. 
PROC. AMER. PHILOS. 80C. XLII. 173. Q. PRINTED AUG. 7, 1903. 
