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Analytical Tables of Minerals 
DIVISION II 
MINERALS FORMING ROCKS 
Silica and the Silicates 
Lustre, Unmetallic 
Streak, White or Gray 
The terrane’s or earth’s crust is made out of dif- 
ferent kind of rocks, and these rocks are made out of 
the various minerals met with in nature. Rocks are 
distinguished from each other by the kind of minerals 
forming them; it is, therefore, necessary that we be able 
to identify these minerals in order to make the proper 
classification of rock formations. 
In the following division only the silicon minerals, 
formings rocks, are described ; these include also many 
varieties possessing considerable commercial value, and 
when occurring in workable quantities they might be 
termed “ores.” The minerals of calcium and aluminum 
are important minerals of the rock forming kind, but 
they are here included under Division I, with the ores. 
