376 



DESCRIPTIVE MINERALOGY. 



Fig. 399. 



Fig. 400. 



vein of granite traversing gneiss, and is associated with tourmaline, garnet, apatite, feldspar 

 and mica. Its colour is usually yellowish green. 



The crystals of chrysoberyl at this locality some- 

 times exhibit the primary form, and sometimes that 

 represented in Fig. 399, which was first noticed by 

 Dr. G. Troost,* the anamorphique of Haiiy, in 

 which the shorter terminal edges are replaced by 

 the planes i : i on i 120°. Also Fig. 400, in which 

 the lateral, as well as the sliorter terminal edges 

 are replaced by single planes. M on s 125° 16'; 

 T on 5 144° 44'. Most commonly, however, the crys- 

 tals are flat compound ones assuming a variety of 

 forms, as represented in Figs. 401, 402, 403, 



M 



M 



Fig. 401. 



Fig. 402. 



Fig. 403. 



404, 405, 406, 407 and 408; the striae 

 being in most cases distinclly marked, 

 as represented in the cuts. The man- 

 ner in which these are produced will, 

 I think, be understood by an inspection 



Fig. 404. 



Fig. 405. 



Fig. 406. 



Fig. 407. 



Journal of the Academy of Natural Sciences of Philadelphia, III, 293. 



