CHAPTER XXXI. 

 MINERALOGY AND CRYSTALLOGRAPHY. 



THE MINERALS CHARACTERISTICS CRYSTALS AND THEIR FORMS 



DESCRIPTIONS OF MINERALS. 



MINERALS are constituent parts of the earth. All parts of minerals are 

 alike. There are simple minerals and mixed. The former are the true 

 minerals, and are generally considered under the heading MINERALOGY. 

 The others constitute a branch of GEOLOGY, as they form aggregate masses, 

 and as such compose a large portion of the earth. We must learn to 

 distinguish minerals and crystals as inorganic forms of nature. In the 

 animal and vegetable kingdoms we have forms which are possessed of organs 

 of sight, smell, taste, and certain structures indispensable to their existence 

 and development. But in minerals we have no such attributes. They are 

 INORGANIC, and have a similar structure ; a fragment will tell us the story 

 as well as a block of the same mineral. These inorganic substances are 

 possessed of certain attributes or characteristics. We find they have FORM. 

 They have chemical properties, and they behave differently when exposed 

 to light and electricity. They are generally solid. All the elements are 

 found in the mineral kingdom, and a mineral may be an element itself, or a 

 chemical combination of elements. These compounds are classed according 

 as the combination is more or less simple. An alliance of two elements is 

 termed a binary compound, of three a ternary compound, forming a base 

 and an acid. 



We have learnt from our chemistiy paper that there are between sixty 

 and seventy elementary bodies in nature. When we speak of " elements," 

 we do not mean to apply the popular and erroneous definition of the word. 

 Earth, air, fire, and water are not elements ; they are compounds, as we 

 have seen. The list of elements has been given ; we will now give the 

 names of the more important minerals. We have no space for a detailed 

 description, but in the British Museum the cases contain some hundreds, 

 and the student will find them classified and described with the greatest 

 care, and according to the arrangement of Berzelius. 



PRINCIPAL MINERALS AS ARRANGED BY PROFESSOR. ANSTED. 



i. 



Diamond. Lignite. Quartz. Flint. 



Graphite. Bitumen. Ameth>st. Jasper. 



Anthracite. Amber. Agate. Opal. 



Coal. Sulphur. Chalcedony. 



