340 
DESCRIPTIVE MINERALOGY. 
pearance, with deep reentering angles on the sides. The summits are truncated at the termi¬ 
nal edges, and slightly bevelled in the direction of the laminae of the crystal, which is also 
the case with the cuneiform additions.* 
Fig. 332. 
Rockland County. It is found in minute crystals in veins, with other zeolitic 
minerals, in the greenstone at Piermont. Fig. 332 represents a form observed 
here and at Bergen hill, New-Jersey. The specimens from the latter locality far 
exceed in beauty those heretofore found at Piermont. The crystals are nearly 
transparent, and although small, present very highly finished and brilliant faces. 
At Bergen hill, this mineral is also found in grouped or fasciculated crystals of a 
straw-yellow colour. 
Fig. 333. 
Westchester County. Near West-Farms, stilbite occurs in crystals lining the walls of 
seams in gneiss, with chabasite, heulandite and epidote. The colour varies from pale to deep 
red. It is also found near Bronx creek, in white six-sided tables, in an aggregate of epidote, 
hornblende, quartz and carbonate of lime, and in gneiss near Yonkers. 
This mineral has recently been obtained in scopiform crystals of a dull 
yellow colour, sometimes with perfect terminations, near Peekskill. The 
vein is apparently from one half to three quarters of an inch wide, and is 
in a decomposing slate. The form represented in Fig. 333, has been found 
at this locality. 
In Connecticut, stilbite is met with in seams in gneiss at Hadlyme, 
associated with heulandite, chabasite, etc. It is also found at Saybrook in 
the same State, and at Bellows-Falls in Vermont. 
HEULANDITE. 
[In honour of Mr. Heuland, of London.] 
Stilbite. Hauj and Cleaveland. — Foliated Zeolite. Werner. — Hemi-prismatic Zeolite, or Heulandite. Jameson. — 
Hemiprismatischer Kuphon-Spath. Mohs. — Heulandite. Beudant, Phillips, Shepard and Dana. 
Description. Colour white, grey, red and brown. It occurs re¬ 
gularly crystallized ; also massive, and often globular. Primary form 
a right oblique angled prism. Fig. 334. M on T 130°. Cleavage 
parallel with P, highly perfect. Fracture conchoidal. Lustre vitreous, 
except P, which is in a high degree pearly, both as faces of cleavage 
From transparent to translucent on the edges. Hardness from 3.5 to 
4.0. Specific gravity from 2.20 to 2.50. Before the blowpipe, it melts with intumescence, 
emitting at the same time a phosphorescent light. It does not gelatinize with acids. 
Fig. 334. 
and of crystallization. 
Torrey. American Journal of Science . V. 399. 
