W. P. Blake—Crystallized Gold in prismatic forms. 57 
ArT. X.—Crystallized Gold in prismatic forms; by 
Wma. P. BLAKE. 
NEAR Clancey, on Clancey Creek, Jefferson County, Mon- 
tana, minute crystals of gold occur which present the novelty 
of a solid octahedral nucleus, or head, with a long divergeut 
brush-like or prismatic development of the gold on one side, or 
angle, giving the whole the appearance of the drawings usu- 
ally made to represent comets, and as represented in the accom- 
panying figure. The total length of these crystals does not 
exceed from two to three millimeters (about one eighth of 
an inch), and the minuteness of the cross-section of the delicate 
divergent prisms makes it extremely difficult to determine 
their form. They are, also, very brittle, and they appear to 
cleave or break asunder in planes at right angles to their length. 
Under the microscope these prisms are : 
seen to have three or more planes and yoRIR 
they appear to be hexagonal. They taper gradually and uni- 
formly to a sharp point, and are sometimes composite, being 
for part of their length formed of two or more-prisms joined 
side to side, : 
Among the fragments, one larger and broader than the 
others exhibits a solid octahedral nucleus with a flat or plate- 
like projection on opposite sides. This projection shows dis- 
tinctly on one side a line of composition through the center, 
with divergent lines or markings at an angle of 46° with the | 
medial line, corresponding in angle and in direction with small 
planes on the edges. The same side of this plate which shows 
the medial line of composition is slightly trough-shaped, being 
formed of two plane surfaces inclined towards the medial line. 
The opposite side is rough, with angular projections. 
These plate-like projections from the octahedron are much 
larger than the prisms, buat it is probable that the origin and 
crystallization of both are similar. The plates have the appear- 
ance of being formed by the combination or twinning of octa- 
hedrons parallel with their faces with their main axes inclined 
towards each other at an angle of 60°. 
HexaGonat Prisms or Goup. 
At Sonora in Tuolumne County, California, I obtained some 
Ne ago from the late Dr. Snell a sample of very small but 
rilliant prisms of gold. Under the microsco are seen 
pe these 
to be hexagonal prisms with smooth and brilliant planes and 
terminated at one or both ends with a pyramid. They appear 
Q, 
