CHAPTER II. 



GRANITE. 



GRANITE is a compound of three minerals, viz: quartz, 

 feldspar and mica : the different ingredients are sometimes in 

 coarse crystaline fragments, and in other cases so fine as to 

 be scarcely distinguishable by the naked eye. Granite is 

 most usually of a whitish or flesh color, it has, however, other 

 tints. Feldspar predominates in the composition of granite, 

 while the mica is in the smallest quantity. "These three 

 minerals are united in what is termed confused crystallization: 

 that is, there is no regular arrangement of the crystals in 

 granite as in gneiss." The coarse grained granites contain 

 the most interesting specimens of simple minerals, while the 

 finer kinds are best for architectural purposes. 



Granite often preserves a uniform character through a great 

 extent of country, forming rounded hills: it is sometimes, 

 though not generally, subdivided by fissures into masses of a 

 cuboidal and columnar form. Where it is naked at the 

 surface, and exposed to atmospheric changes and action, it is 

 in a crumbling state, and covered with a scanty vegetation. It 

 is remarked by Lyell, that all granitic rocks are frequently 

 observed to contain metals, at or near their junction with 

 stratified rocks. 



Granite is supposed to be the oldest, most abundant and 

 important of all the unstratified rocks. There are several 



