256 



PHYSIOGRAPHY. 



Herderite. 



3. It has hitherto been found only at Schwarzenberg in Saxony, in 

 beds in gneiss, accompanied by Blende, Quartz, Fluor and Calcareous 

 Spar. 



HEMATITE. (See Limonite and Specular Iron.) 

 HERDERITE. Prismatic F 1 u o r- H al o i d e. 



Primary form. Right rhombic prism. M on M' =* 

 115 53'. 



Secondary form. 



Fig. 240. 



JM: 



M 



t on t' 

 t on* 



115 53' 

 115 7 



p onp - 141 16 



Cleavage distinct parallel to faces M, but interrupted ; 

 also perpendicular to the axis, the latter only in detached 

 portions of very bright and even faces ; faint indications 

 parallel to P,jp. Fracture small conchoidal. Surface, M 

 very smooth, and delicately streaked parallel to its edges 

 of combination with P, and resembling in this respect the 

 faces p. 



Lustre vitreous, slightly inclining to resinous. Color 

 several shades of yellowish and greenish-white : streak 

 white, strongly translucent. 



Very brittle. Hardness =5-0. Sp. gr. =2-985. 



1. The present species has been confounded with Apatite, which it 

 exceedingly resembles in several properties ; but the different aspect of 



