70 THE PROSPECTOR'S HANDBOOK. 



The oxide of manganese, when heated with borax on a 

 platinum wire, colours the bead violet to black when hot, 

 reddish violet when cold, in the O.F. ; colourless when hot, 

 colourless to rose colour when cold, in the R.F. If a 

 mineral together with carbonate of soda be fused, a greenish 

 glass will suggest the presence of manganese. 



Wad (bog manganese) is an earthy or compact variety of 

 manganite, a mineral which differs from the black oxide in 

 containing 10 per cent of water. Psilomene is a hydrous 

 oxide of manganese which contains baryta and other sub- 

 stances. When heated with borax produces a violent 

 effervescence. Oxides dissolve in hydrochloric, also in a 

 boiling solution of citric acid. 



Manganese spar (of a reddish colour) consists of man- 

 ganese protoxide, silica, &c. 



Manganese deposits occur in different parts of the world 

 and seem to have been derived from the metal originally 

 scattered about in rocks of the ancient formations. 



MERCURY. 



If heated in a glass tube together with carbonate of soda, 

 mercury compounds yield a sublimate of mercury on the 

 cold part of the tube. 



Native Mercury. 



Is sometimes found as fluid globules of a tin-white colour. 

 S.G. 13-6. Is volatile before theB.F., and easily dissolve* 

 in nitric acid. 



Cinnabar (sulphide of mercury). 



This is the ore from which commercial mercury is ob- 

 tained. Sometimes found massive, with a granular struc- 

 ture, sometimes in a crystallized form, the crystals being 

 brilliant, transparent, and of a beautiful carmine colour. 



Colour generally red, sometimes bright red; also 



brown, brownish black, &c. 

 Streak red. 

 Lustre unmetallic. 



