MINERALOGY. 



Minerals. 



Minerals are the materials of which the earth consists, and 

 plants and animals the living beings over the surface of the 

 mineral-made globe. A few rocks, like limestone and quartz- 

 yte, consist of a single mineral in more or less pure state ; but 

 the most of them are mixtures of two or more minerals. 

 Through rocks of each kind various other minerals are often 

 distributed, either in a scattered way, or in veins and cavities. 

 Gems are the minerals of jewelry; and ores, those that are im- 

 portant for the metal they contain. Water is a mineral, but 

 generally in an impure state from the presence of other miner- 

 als in solution. The atmosphere, and all gaseous materials set 

 free in volcanic and other regions, are mineral in nature, 

 although, because of their invisibility, seldom to be found 

 among the specimens of mineral cabinets. Even fossils are 

 mineral in composition. This is true of coal which has come 

 from buried plant-beds, and amber from the buried resin of 

 ancient trees, as well as of fossil shells and corals. 



It is sometimes said that minerals belong to the mineral 

 kingdom, as plants to the vegetable kingdom, and animals to 

 the animal kingdom. Substituting the term inorganic for min- 

 eral, the statement is right ; for, as there are the two kingdoms 

 of life, so there is in Nature what may be called a kingdom, or 

 grand division, including all species not made through the 

 organizing principle of life. Bat this inorganic kingdom is not 

 restricted to minerals ; it embraces all species made by inor- 

 ganic forces — those of the earth's crust or surface, and, also, 

 whatever may form under the manipulations of the chemist. 

 The laws of composition and structure, exemplified in the consti- 

 tution of rocks, are those also of the laboratory. A species made 



