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A mineral may be defined as a homogeneous solid, of definite chemi- 

 cal composition, occurring in nature, but not of apparent organic 

 origin. 



I. Minerals. 



1. Mixtures. 



Granite, quartz, mica and feldspar. 



2. Compounds. 



Quartz silicon and oxygen. 



3. Elements. 



Oxygen, gold, mercury. 



An element is a substance which cannot be reduced into other ele- 

 ments; silver, gold. 



4. Important Elements in Earth's Crust. 



(a) Gaseous. 



Oxygen, hydrogen, nitrogen, chlorine. 



(b) Liquid. 



Mercury. 



(c) Solid. 



Silicon, aluminum, iron, calcium, magnesium, potassium, 

 sodium, carbon, phosphorus, sulphur. 



5. Important Minerals in Earth's Crust. 



(a) Quartz. 



Flint; hornstone; white, brown, yellow or black pebbles, 

 uniform in color; sand; amethyst; false topaz; smoky 

 quartz; cairngorm stones; agate, cornelian. 



(b) Silicates rocks containing silica. 



Feldspar, mica, hornblqnd, augite or pyroxene, garnet, ser- 

 pentine, chlorite, tourmaline, oliviue. 



(c) Carbonates compounds of carbonic acid. 



Calcite calcium carbonate; magnesium limestone or dolo- 

 mite. 



(d) Sulphates compounds of sulphuric acid. 



Gypsum sulphate of lime; barite barium sulphate; cop- 

 peras or green vitriol iron sulphate. 



(e) Ores metal bearing minerals. 



Iron pyrites; chalcopyrites or copper pyrites; magnetite or 

 magnetic iron ore; hematite or specular iron ore; limonite 

 brownish yellow iron ore; siderite or spathic iron ore; 

 chalcopyrites, or yellow copper ore; galenite, or lead ore; 

 malachite green copper carbonate; azurite blue copper 

 carbonate. 



