PHYSIOGRAPHY* 143 



Quartz. 



Fig. 359. The primary form, having its lateral angles 

 leeply truncated, so as to produce a long prism. P on r 

 = 141 40'. Fig. 360. The primary form, having its lat- 

 eral angles replaced. by tangent planes, (r,) and by trian- 

 gular planes resting on the upper edges of the rhomboid. 

 P on z =133 48'. r on z =141 40'. Fig. 361. The 

 iame, in which the planes r are much .extended, (prisme 

 nsalterne. HAUY.) A common form. Fig. 362. The 

 iame, in which the planes z have the same size with P. 

 (prisme. HAUY.) A common form, but rarely perfectly 

 regular in the size of similar planes. Fig. 363. The same 

 as Fig. 361, with the omission of r. P on z"=103 20'. 

 (dodecaedre. HAUY.) Rare. Fig. 364. Similar to Fig. 

 361, but having two opposite sides of the prism, and the 

 adjacent pyramidal faces unduly extended, (prisme corn- 

 prime. HAUY.) Not very common. Fig. 365. Similar 

 to Fig. 363, but having two adjacent faces of the prism 

 unduly extended, (prisme sphalloide. HAUY.) Fig. 366. 

 Similar to Fig. 361, but having one face of the pyramid 

 unduly extended, (prisme haloids. HAUY.) Common. 

 Fig. 367. Similar to Fig. 361," with the addition of the 

 rhomboidal truncations of the alternate lateral, solid angles. 

 r on s =142. P on s =151 7'. Common. Fig. 368. 

 P on =145 22'. c on a =159 50'. .conP = 165 

 30'. z" on a = 111 15'. z on a = 137 51'. z on e 

 = 145 30'. a on e =175 30'. Very rare. Fig. 369. 

 Fig. 361, having the edges of the pyramids truncated, f 

 on z =141 40'. (emargine. HAUY.) Very rare. Fig. 

 370. r' on g = 178 32'. P on g = 143 32'. (hyperox- 

 ide. HAUY.) Fig. 371. Fig. 361, with the terminal edges 

 of the prism replaced by single planes, r on m = 168 



