114 FIELD GEOLOGY. 



THE MORE COMMON METALS, 



their usual modes of occurrence, and tests* for approxi- 

 mate determination. 



Metals are characterised by their peculiar (metallic) 

 lustre and great specific gravity. Some are found 

 " native/' but they usually occur in the state of ores, 

 that is, in chemical combination with other substances, 

 generally in veins in the older rocks, or as concretions 

 in interstratified beds. 



The following Metals occur in a Native State : 

 p , , /-In plates, nuggets, grains, and threads among 



'' -< the older rocks, or alluvial deposits de- 

 Silver, J ,,! P 



V rived tnereirom. 

 Platinum, in grains. 

 Copper, in plates and threads. 



The following Metals occur as Ores, in Veins : 

 Silver. 



Copper, as Blue Vitriol, Glance, &c. 

 Lead, as Galena. 

 Iron, as Vivianite, Copperas, &c. 

 Tin, as Cassiterite. 

 Zinc, as Calamine, Blende. 



The following Metals occur as Ores, in Beds : 



Copper, as Malachite, Pyrites, &c. 



Lead, as Galena. 



Iron, as Clay-iron ore, Pyrites, Glauconite (dissemi- 

 nated grains), Chalybite, Haematite, Magnetite, &c. 



Manganese, as Pyrolusite, Wad. 



Zinc, as Calamine, Blende. 



See Preceding Tables. 



