PHYSIOGRAPHY. 133 



Clausthalite. 



CLAUSTHALITE. Paratomous Polypoione- 



Gl an c e. . 



Massive: individuals granular :* the larger ones having 

 one bright cleavage ; also in minute lamellar masses. 



Lustre metallic. Color lead-grey, with a tinge of blue. 

 Streak dark grey. 



Hardness, below Galena. So. gr. =6 '8. 



1. Heated in a glass tube before the blow-pipe, the selenium sublimes 

 and fills the upper part of the tube with crystals of selenic acid. Upon 

 charcoal it smokes, and tinges the flame of the blow-pipe blue. Cold ni- 

 tric acid, after some time, causes the mass to assume a red color in conse- 

 quence of the separation of selenium. 



2. Analysis. 



By ROSE. By STROMEYER. 



Lead - 72-3 - - 70-98 



Selenium - 27-7 - - 28-11 

 Cobalt - 00-0 - - 0-83 



3. It is found in the eastern part of the Hartz, at several places not far 

 apart, one of which is Lorenz, near Klausthal; another is near Zorge, 

 in the. veins of iron-ore which traverse the argillite ; and another still is 

 near Tilkerode. The mineral is contained in a dolomite or argillite, 

 accompanied by Malachite and Quartz. 



APPENDIX TO SEL.ENITJRET OF LEAD. 

 i. Seleniuret of Lead with Seleniuret of Cobalt. 

 Sp. gr. = 7 697. Found by ROSE to contain 



Lead 63-92 



Cobalt 3-14 



Selenium 31-42 



Iron 0-45 



Loss 1'07 



It is found near Klausthal, engaged in dolomite. 



ii. Seleniuret of Lead with Seleniuret of Copper. 

 Sp. e;r. = 5-0 ... 7-0. Analysis by ROSE. 



5 Selenium - - - 29-96 



Iron with traces of lead 0-44 



Lriad - - - 59-67 



Iron - - * 033 



Copper 7-86 



Undecomposed and loss - 1*74 

 12 



