Arrangement of Minerals. 



Genus V. Emerald. 



Ilemiprismatlc. Rhombohedral. Cleavage distinctly rhombohe- 

 dral, axotomous and peritomous ; or very perfectly prismatoidal. Hard- 

 ness = 7.5 — 8.0. Sp. gr. = 2.6 — 3.2. 



1. Prismatic Emerald, or Euclase. 2. Rliomboliedral Emerald, or 

 Phenakitc. 4. Dirhombohedral Emerald {Precious Emerald or 

 Smooth Emerald J and Beryl or Striated Emerald), 



Genus VI. Quartz. 

 Rhombobedral. Prismatic. Amorphous. Cleavage not axotomous. 

 Hardness = 5.5 — 7.5. Sp. gr. = 1.9 — • 2.7. 



1. Prismatic Quartz, or lolite. 2. Rhombohedral Quartz, or Rock- 

 crystal {Common Quartz j S^c). 3. Uncleavable Quartz, or Opal. 

 4. Empyrodox Quartz {Obsidian, Pitchstone, Pumice, (Sfc). 



Genus VH. Axinite. 

 Tetarto-prismatic. Cleavage imperfect. Colour not inclined to 

 yellow. Hardness = 6.5 — 7.0. Sp. gr. = 3.0 — 3.3. 

 1. Prismatic Axinite. 



Genus VHI. Chrysolite. 

 Prismatic and Hemiprismatic. Cleavage very imperfect. Colour 

 green, brown ; both inclining to yellow ; yellow. Pure vitreous lustre. 

 Hardness = 6.5 — 7.0. Sp. gr. = 3.1 — 3.5. 



1. Prismatic Chrysolite or Common Chrysolite. 2. Hemiprismatic 

 Chrysolite, or Chondrodite. 



Genus IX. Boracite. 

 Tessular. Hardness = 7.0. Sp. gr. = 2.8 — 3.0. 

 1. Tetrahedral Boracite. 



Genus X. Tourmaline. 

 Rhombohedral. Cleavage imperfect. Hardness = 7.0 — 7.5. 

 Sp. gr. = 3.0 — 3.2. 



1. Rhombohedral Tourmaline. 



Genus XI. Garnet. 

 Tessular. Pyramidal. Prismatic. Cleavage imperfect or pris- 

 matoidal. Hardness = 6.0 — 7.5. Sp. gr. = 3.1 — 4.3. 



1. Pyramidal Garnet, or Vesuvian. 2. Tetrahedral Garnet, or Hel- 

 vine. 8. Dodecahedral Garnet {Precious Garnet, d:c.). 4. Hexa- 

 hedral Garnet, or Pyrope. 5. Prismatoidal Garnet, or Grenatlte. 



Genus XII. Zircon. 

 Pyramidal. Hardness = 7.5, Sp. gr. =^4.5—4.7* 

 I. Pyramidal Zircon. 



