370 Arrangement of Minerals. 



CLASS III. 



Characters of the Class. — Specific gravity less than 1.8. If 

 liquid, the smell is bituminous. If solid, is tasteless. 



Order I. RESIN. 



Fluid and solid. Hardness = 0.0 — 2.5. Sp. gr. = 0.8 ~- 

 1.6. If sp. gr. = 1.2 and more, the streak is white or grey. 



Genus I. Mellite, or Honeystone. 



Pyramidal. Streak white. Hardness = 2.0 — 2.5. Sp. gr. = 

 1.4 — 1.6. 



1. Pyramidal Mellite. {Mellate of alumina). 



Genus II. Mineral Resin. 



Amorphous. Hardness = 0.0 — 2.5. Sp. gr. = 0.8 — 1.6. 

 If the sp. gr. = 1.4 and more, the streak is white. 



1. Yellow Mineral Resin, {Amber). 2. Brown Mineral Resin 

 {Idrialite of Schr otter). 8. Black Mineral Resin {Naphtha, Pe- 

 troleanij Asphaltum or Mineral Pitchy S^c.) 



Order II. COAL. 



Solid. Streak brown, black. Hardness — 1.0 — 2.5. Sp. 

 gr. =1.2 — 1.6. 



If the sp. gr. =1.4 and more, the streak is black, and with- 

 out considerable lustre. 



Genus I. Mineral Coal. 



Form irregular. Hardness = 1.0 — 2.5. Sp. gr. = 1.2 — 1.6. 



1. Bituminous Mineral Coal {Brown Coal and Black Coal). 2. Non- 

 bituminous Mineral {Anthracite, or Glance-Coal). 



