SILICA. 



303 



Fig. 233. 



Fig. 234. 



Fig. 233, the same with the ter- 

 minal planes differing from the 

 preceding: / on Z 110^ 2' {She- 

 pard) ,•* ditetraedre of Haiiy. 



Fig. 234, hisunitaire of Haijy. 



Fig. 235, prisms low, the face 

 X very narrow. 



238. 



Fig. 237. 



JI 



M 



Fig. 236, same as the preced- 

 ing, with the face x much extend- 

 ed. 



Fig. 237, the same as the pre- 

 ceding, the face x much extended, 

 and with the additional plane i : 

 i upon X 129° 8'. 



Also the form represented in 

 Fig. 238. 



Near the village of Amity, there are several localities of massive and crystallized horn- 

 blende of various colours, and exhibiting a variety of crystalline forms. 



The following, in addition to those already introduced, have been found in the town of 

 Warwick, viz : 



Fig. 239. 



Fig. 240. 



Fig. 241. 



Fig. 239, the primary, with the 

 obtuse lateral edges replaced by 

 tangent planes. 



Fig. 240, the same, with the 

 acute lateral edges replaced by 

 tangent planes. 



Fig. 241, the same with tlie ob- 

 tuse and acute lateral edges re- 

 placed by planes. 



• The measurement of ( on /, here given, is from Shepard. Haiiy lias the angle / on / 149° 3S' which is the same as r on r. 

 Crystals with the lesser angle are cjuite rare in this county. 



