INTRODUCTION. 



This book is not intended, in the strict sense of the term, to be a Manual of 

 Mineralogy, but, believing that a concise description of the modes in use for 

 distinguishing between different minerals will assist the student in recog- 

 nising them, the plan of a mere Glossary has been departed from, and brief 

 hints on the nature of minerals have been introduced. 



It must be remembered, however, that there is no short cut to a know- 

 ledge of minerals. Mineralogy, like the other sciences, demands industry 

 and attention ; and to become an accomplished mineralogist much and care- 

 ful study must be devoted to the subject ; an acquaintance with various 

 other branches of science must be brought to bear on it, while, above all, 

 the eye should be rendered familiar by constant inspection with the forms 

 and appearances of minerals, and with their physical properties. This eye- 

 knowledge (as it may be termed) can only be acquired by long and diligent 

 practice, — by actual examination — and by handling the specimens them- 

 selves, no opportunities of doing which should be neglected. 



To become well versed in mineralogy involves also a knowledge of Physics 

 and Chemistry. By means of the first we make ourselves acquainted with 

 the physical properties of minerals ; while the second teaches us the nature 

 of their chemical composition. It appears necessary, therefore, to refer to 

 the bearings of these sciences on mineralogy ; but in the limited space to 

 which these remarks must be confined, it is only possible to do so in a very 

 brief manner. 



GEKEKAL CHAEACTEES. 

 External Form and Structure. 

 Characters depending on light. 



Colour. 



Transparency. 



Lustre. 



Optical Properties. 

 Refraction. 

 Double Refraction. 

 Dichroism. 

 Polarization. 



Physical Properties. 

 Specific Gravity. 

 Phosphorescence. 

 Fluorescence. 

 Electricity. 

 Magnetism. 



other characters. 



Stain. 



Streak. 



Taste. 



Odour. 



Adhesion to the tongue. ' 



FeeL 



Characters dependent on cohesion. 



Frangibility, or Tenacity. 



Fracture. 



Hardness. 



Toughness. 



Chemical characters. 



Action of the Blowpipe. 

 Action of Acids. 



