260 
DESCRIPTIVE MINERALOGY. 
Greene County. Rock crystal is often found in seams and veins in the slate in various 
parts of this county. The best locality, however, at present known, is at Diamond hill, in 
the village. The quartz is imbedded in a stiff clay, between layers of the slate. A great 
variety of crystalline forms have been found at this place. Crystals are said to have been 
here obtained, weighing two or three pounds. They sometimes had cavities containing a 
liquid, a bubble of air, and some black or brown particles. In one specimen the cavity was 
five-eighths of an inch long and a quarter of an inch wide, the bubble occupying nearly half 
the cavity.* 
The specimens recently found at this locality will not by any means compare in beauty 
with those which have been obtained in Herkimer county, but many of them present very 
interesting modifications. They are seldom limpid throughout, and a large majority of the 
specimens are imperfect. They seem, however, to be still abundant in the clay-filled cavities 
of the slate. The forms which I have observed here, are those represented as follows, viz : 
Fig. 130, prisme of Haiiy (p. 257.) 
The rhombifere of Haiiy, similar to the preceding, with the addition of the rhomboidal 
truncations of the alternate, lateral solid angles. Fig. 131. P on s, or z on s 151° T\ r on s , 
or r' on s 142°. 
The same as Fig. 130, but having two opposite sides of the prism and the adjacent pyra¬ 
midal faces unduly extended: prisme comprime of Haiiy, Fig. 132. 
Prisme sphalloide of Haiiy, Fig. 133. 
Fig. 131. Fig. 132. Fig. 133. 
* Cleavsland’s Mineralogy. 
