56 PHYSIOGRAPHY. 



Beaudantite Bismuth-Blende. 

 Secondary form. 



Fig. 58. 



Cleavage parallel with a. 



Surfaces curved ; generally brilliant. 



Lustre resinous. Color black ; in thin fragments, trans- 

 lucent, and of a deep brown color. Streak greenish-grey. 



Hardness =4-0... 4-75. 



Compound varieties. Massive : composition not descri- 

 bed. 



1. It consists of the oxides of iron and lead. 



2. Its locality is Horhausen on the Rhine, where it seems associated 

 with Brown Iron-Ore. 



3. The want of a knowledge of the specific gravity of this mineral 

 prevents us from referring it to its natural historical genus. The prop- 

 erties above enumerated, however, prove it with sufficient distinctness to 

 be a peculiar species. 



BI-SELENIURET OF ZINC. (See Rionite.) 



BISMUTH BLENDE. Tetrahedral Bismuth 



B ary te. 



Primary form. Unknown.* Implanted globular shapes. 

 Massive : composition thin columnar, impalpable, also cur- 

 ved lamellar. 



k 



" HARTMANN gives the Tetrahedron as the primary form of this species, and de- 

 scribes its crystals as occurring in tetrahedra, with their edges deeply bevelled, and 

 like fig. 55, P. I. 



