a New Mineral Species. 273 



a greater number of planes than any of those which have been 

 described by Count BOURNON. I have noted the faces, with the 

 letters received for Axinite by HAUY, and in the Treatise on Mi- 

 neralogy by Professor MOHS, for the sake of an easier compari- 

 son of the analogies among the crystalline forms of the two spe- 

 cies. I obtained the following measurements of the angles : 



r on M = 129 y on r 109 



r on P = 116 s on x = 156| 



M on P = 115 x on t = 164^ 



s on r = 135^ x on y 151 



d on r 124^ t on y = 



These angles are given merely as rude approximations to the 

 true angles of the crystal, as, besides the use of the common 

 goniometer, I was obliged to take impressions from them in seal- 

 ing-wax, to make them at all fit to be measured with the assist- 

 ance of the reflective goniometer. The surface is far from pre- 

 senting a good polish, or high degree of lustre ; the inclined faces 

 s, x, t, and y, are more perfect in this respect than those which 

 are parallel to the axis. The face M in particular is very rough 

 and uneven. The inclination of r on P is more easily ascer- 

 tained. The edge between P and M is also sometimes replaced 

 by a rough face. 



Faint traces of cleavage are observable parallel to P and r ; 

 but they are very indistinct and interrupted. Fracture is imper- 

 fect conchoidal. 



The lustre is imperfect metallic, if any thing inclining to re- 

 sinous ; the colour black, verging upon green or brown : the co- 

 lour of the powder or streak is greenish-grey, also a little brown- 

 ish. It is opake, only the edges of very thin splinters are some- 

 what translucent, and of a dark yellowish-brown colour. 



M m 2 



