TABLE OF CONTENTS. 



MINERALOGY. 



PAGE 



Minerals : General Eemarks 1 



I. CRYSTALLIZATION OF MINERALS: CRYSTALLOGRAPHY. 



1. General Remarks on Crystallization 4 



2. Descriptions of Crystals 8 



Explanation of Terms 8 



Measurement of Angles ; Goniometers 9 



I. Systems of Crystallization : Forms and Struc- 



ture of Crystals 14 



1. Isometric System 17 



2. Dinietric or Tetragonal System 30 



3. Trimetric or Orthorhcnibic System 3? 



4. Monoclinic System 40 



5. Triclinic System . . 43 



6. Hexagonal System 45 



1. Hexagonal Section 46 



2. Rhombohedral Section 49 



7. Distinguishing Characters of the Systems 54 



II. Twin or Compound Crystals 55 



III. Crystalline Aggregates 58 



II. PHYSICAL PROPERTIES OF MINERALS. 



1. Hardness 63 



2. Tenacity 64 



3. Specific Gravity 64 



4. Refraction and Polarization 66 



5. Diaphaneity, Lustre, Color 70 



6. Electricity and Magnetism 73 



7. Taste, Odor 74 



V 



