68 PHYSIOGRAPHY. 



It resembles paratomous Augite-spar in a remarkable de- 

 gree, particularly in regard to form and regular composi- 

 tion. It has been found by BERZELIUS to consist of 



Silica 65-25. 



Oxide of Iron 31-25. 



Oxide of Manganese 1-08. 



Lime 0-72. 



Soda 10-40. 



It melts readily before the blowpipe, into a black globule. 

 It is found at Eger in Norway, imbedded in granite. 

 Its name is derived from *^j a point, from the form of 

 the crystals. 



ALLANITE. 

 ORE. 



Allanite. THOMSON. Trans. Roy. Soc. Edinb. Vol. VI. 

 p. 371. Prismatic Cerium-Ore or Allanite. JAM. Syst. 

 VoL III. p. 181. Man. p. 319. Allanite (in part). 

 PHILL. p. 264. 



Tetarto-prismatic. Combination observed similar 

 to Fig. 185. Inclination of r on M = 129, 

 r on P= 116, Mon P = 115 ; s on r = 135^, 

 d on r = 1244, y on r = 109, * on x = 156f , 

 x on t = 164J, x on y = 151, tony = 166 J, 

 AP. 



Cleavage parallel to r and P indistinct. Fracture 

 imperfect conchoidal. 



Lustre imperfect metallic. Colour brownish- or 

 greenish-black. Streak greenish-grey. Opake, 

 faintly translucent in thin splinters, and brown. 



Brittle. Hardness = 6-0. Sp. Gr. = 4 001, BOURNON^ 



Allanite froths before the blowpipe, and melts imperfect- 

 ly into a black scoria. It gelatinises in nitric acid, and 

 consists, according to Dr THOMSON, of 



