72 CLASSIFICATION OF MINERALS. 



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species being each a simple element alone, and others con- 

 sisting of two or more elements in a state of combination 

 ~^nX various native metals, as native gold, silver, copper, 

 ] mercurv, are some of the elements. Iron ores are com* 

 pounds \f the element iron with some other element or 

 elements, as oxygen, sulphur, or oxygen and carbon, &c. 

 Marble is a compound of three elements, calcium, oxygen 

 and carbon. Water consists of two elements, hydrogen and 

 oxygen. Diamond is the simple element carbon, which is 

 dentical with pure charcoal. All the so-called elements oi 

 matter are found in the mineral kingdom, either in a pure or 

 combined state; and.it is the object of chemical analysis 

 to ascertain the proportions of each in the constitution of 

 the several minerals. Upon these results depends to a great 

 degree our knowledge of those relations of the species upon 

 which the classification of minerals is based. 



The number of elemental substances in nature, according 

 to the most recent results of chemistry, is sixty. Of 

 these, forty-seven are metals, and five are gases ; the rt*- 

 I mainder, as, for instance, sulphur and carbon, are solids 

 without a metallic luster, excepting one (bromine) which i^ 

 a liquid at the ordinary temperature. Of these fixty 

 elements, very much the larger part are o c rare occurrence 

 in nature. The rocks of the globe, with their most common 

 minerals, are made up of about thirteen of the elements. 

 These are the gases oxygen, hydrogen, nitrogen; chlorine ; 

 the non-metallic elements carbon, sulphur, silicon ; tfye metals 

 calcium, (basis of lime,) sodium, (basis of soda,j pdtassium, 

 (basis of potash,) magnesium, (basis of magnesia,) ajdminium. 

 (basis of alumina, the principle constituent of clay,) with 

 iron. The element silicon combined with oxygen, forms 

 silica. In this state, it is the mineral quartz, the most 

 common in the constitution of the rocks of the globe : it 

 is a constituent of granite, mica slate and the allied rocks, 

 of the hard granular quartz rock ; and it is the essential part 

 of all sandstones and millstone grits, as well as the principal 

 ingredient of the sands of the sea shore and of most soils. 

 Combined with lime, potash or soda, magnesia or alumina, 

 and often with iron, it forms nearly all the other mineral in. 



What is the number of elements, and how many are metals ? How 

 many constituents are essential to the rocks of the globe, and what ar« 

 they 1 What is said of quartz 1 



