OBDERII. BRACHYTYPOUSPARACHROSE-BARYTE. 103 



rounded. The common lens is produced by 

 continued striae between R 1 and R. 



Lustre, vitreous inclining to pearly. Colour vari- 

 ous shades of yellowish-grey, passing into ash- 

 and greenish-grey, also into several kinds of 

 yellow, white, and red. Streak white. Trans- 

 lucent, in different degrees. 



Brittle. Hardness = 3-5. . .4-5. Sp. Gr. = 3-829, 

 a crystallised variety from Pfaffenberg in Anhalt. 



Compound Varieties. Striae upon the faces of R, 

 in the direction of the horizontal diagonals, and 

 faces of composition parallel to R 1, as in the 

 preceding species, shew that there is also here regu- 

 lar composition according to the same law. Botry- 

 oidal and globular shapes : composition columnar ; 

 surface drusy. Massive: composition granular, pass- 

 ing into impalpable. 



OBSERVATIONS. 



1. The massive varieties of the present species are often 

 regularly compound in the direction of the faces of R 1, 

 as in Fig. 131. It is sometimes possible to obtain from 

 them by fracture, the form of R 1, bounded on all sides 

 by faces of composition, without presenting a single real 

 face of cleavage. There is no distinct cleavage parallel to 

 the faces of R 1 . The saddle-shaped lenses are in part 

 composed of several individuals nearly in parallel position, 

 but the axes of which are slightly diverging. Also the 

 curvature of faces of cleavage often originates in composi- 

 tion. Vol. I. Fig. 80. 



Different opinions prevail among mineralogists in regard 

 to the determination and classification of the present spe- 

 cies. In the Wernerian system it forms an undivided 

 species in his Iron-genus. It was formerly united by 



