3G8 Arrangement of Minerals, 



perfect. Colour lead-grey, steeUgrey, pinchbeck-brown. In thin 

 plates flexible ; elastic. Hardness = 1 .0 — 2.5. Sp. gr. = 4.2 — 8.5. 

 1. Elastic EiUomous Glance. {Molyhddns'ilher , W.) 2. Pyramidal 

 Eutomous Glance. {^Tellurc natif Auro-plomhifere, H.) 3. Rhom- 

 bohcdral Eutomous Glance. {Tetradymite, Haid. Markasit- 

 glanz, Br.) 4. Dirhombohedral Eutomous Glance (Molybdena- 

 glance. Molybdene Sulphure, H.) 6. Prismatic Eutomous 

 Glance. {Sternbergite, Haid.) 



Genus VI. Bismuth-Glance. 

 Prismatic. Colour lead-grey. Hardness = 2.0 — 2.5. Sp. gr. 

 z= 6.1 — 6.8. If the colour is blackish lead-grey, the Sp. gr. is = 6.7 

 and more ; if pure lead -grey, the Sp. gr. = 6.4, and less. 



1. Prismatic Bismuth-Glance. {Bismuth Sulphure, H.) 2. Prisma- 

 toidal Bismuth-Glance. {Nadelerz, W. .Bismuth Sulphure 

 Flombo-cuprifere, H.) 



Genus VII. Antimony-Glance. 

 Prismatic. Colour steel- grey, pure lead-grey. Cleavage perfect. 

 Hardness = 1.5 — 2.5. Sp. gr. = 4.2 — 5.8. If the sp. gr. 5.3, 

 the hardness = 2.0, and easily broken when in thin plates. If sp. gr. 

 above 5.3, colour is steel -grey, not inclining to lead-grey. 



1. Prismatic Antimony-Glance. {Tellure natif awo-argentifere, H.) 

 2. Prismatoidal Antimony-Glance, or Grey Antimony. (Com- 

 mon Ore of Antimony. Antimoine Sulphure, H.) 3. Axoto- 

 mous Antimony-Glance, or Jamesonite {StahlantimonglanZj Br.) 

 4. Peritomous Antimony-Glance {Sulphuret of Silver and Anti- 

 mony, Philhps). 



Genus VIII. Melane-Glance. 

 Rhombohedral. Prismatic. Colour iron-black. Streak unchanged. 

 Hardness =: 2.0 — 2.5. Sp. gr. = 5.9 — 6.4. 



1. Rhombohedral Melane-Glance. {Sprodglaserz, W. Polybasite, 

 G. Rose.) 2. Prismatic Melane-Glance. {Sprodglaserz, VY. 

 Argent antimonie sulphure noir, H.) 



Order V. BLENDE. 

 Metallic, black ; not metallic. Streak green, red, orange, 

 brown — white. Hardness = 1.0 — 5.0. Sp. gr. = 2.8 — - 8.2. 

 Genus I. Manganese-Blende. 

 Tessular. Streak green. Hardness = 3.5 — 4.0. Sp. gr. = 3.9 



— 4.05. 



1. Hexahedral Manganese-blende {Manganese sulphur^). 

 Genus II. Bismuth-Blende, or Diamond Blende. 

 Tessular, Streak white. Hardness = 4.5 — 5.0. Sp. gr, = 5.8 



— 6.0. 



