368 



Fig. 169. 



DESCRIPTIVE MINERALOGY. 

 Fig. 170. Fig. 171. 



Fig. 172. 



Figs. 135, 136, 149, also occur at this locality, with several other 

 more common forms. 



Crystallized quartz is also found abundantly at Flatbush in this 

 county. Fig. 173 represents a compound crystal from that loca- 

 lity. 



. 174. 



Fig. 175. 



Warren County. On the islands in Lake George, and especially on Diamond island, four 

 miles north of the village of Caldwell, very beautiful transparent crystals of quartz were for- 

 merly found in considerable abundance, in the cal- 

 ciferous sandstone. They were generally six-sided 

 prisms, often with pyramidal terminations, and were 

 sometimes four or five inches long, either loose or in 

 cavities in the rock. One of these forms, described 

 and figured by Dr. G. Troost, the Quartz unibinaire 

 of Haiiy (Fig. 174), is a hexahedral prism with the 

 edges of their bases bevelled. P on o 128° 20'. 

 In the same group were several of this form, and 

 one having some of the solid angles of the prism 

 truncated, forming a combination of the rhomhifere 

 of Haiiy, and of the unibinaire, as in Fig. 175. 

 These crystals were from a quarter to half an inch 

 in length, and were found associated with calcareous spar.* 



* Troost. Journal of the Academy of Natural Sciences of Philadelphia, JI. 212. 



