20 PHYSIOGRAPHY. CLASS II. 



Lustre metallic. Colour lead grey, inclining a 

 little to steel-grey. Streak unchanged. 



Rather sectile. Hardness = 2-0 ... 2-5. Sp. Gr. = 

 6*549, the variety from Rezbanya. 



Compound Varieties. Massive : composition gra- 

 nular, the individuals being of various sizes ; or co- 

 lumnar, individuals straight and aggregated in va- 

 rious directions. 



OBSERVATIONS. 



1. According to SAGE it consists of 



Bismuth 60-00. 



Sulphur 40-00. 



According to this analysis it is Bi S 6 , which corresponds 

 to 59'51 of bismuth, and 40-49 of sulphur. It is volatilised 

 before the blowpipe, and covers the charcoal with a yellow 

 areola. It is easily fusible, and emits continually small 

 drops in a state of incandescence. It is easily soluble in 

 nitric acid, and the solution yields a white precipitate on 

 being further diluted. 



2. Prismatic Bismuth-glance occurs principally in veins, 

 but is found also in beds. It is generally associated with 

 octahedral Bismuth, also with several species of Pyrites, 

 with pyramidal Tin-ore, rhombohedral Quartz, &c. 



3. It is rather a rare mineral. It is found at Altenberg, 

 at Schneeberg, and some other places in Saxony, at Joa- 

 chimsthal in Bohemia, at llezbanya in Upper Hungary, 

 in the latter place in beds ; near Redruth and Botallack in 

 Cornwall ; at Riddarhyttan in Sweden, with uncleavable 

 Cerium-ore ; in the mountains of Beresof in Siberia, &c. 

 Very fine varieties, in large cleavable individuals* are 

 found at Carroek in Cumberland. 



