OCCUKRING IN TASMANIA. 31 



64 SiEGENiTE. — {Sulphide of cobalt and nickel.) 

 Occurs massive, of a steel-grey colour, intermixed 



with magnetite, pyrite, and niccolite. Rocky 

 River Mine. 



65 SoDALiTE. — {G hi or OS Hi cat e of sodium and aluminium.) 



In the elaeolite syenite of Port Cygnet, changed to 

 natrolite. 



66 Spodumene. — (^Aluminium and lithium metasilicate.) 



Variety, triphane. 

 Several thin flakes of this substance have been 

 obtained in alluvial tin workings near Mt. Cameron, 

 with quartz, topaz, and sapphire. It is of the very 

 characteristic yellow-green colour, and quite indis- 

 tinguishable from the clear samples found in 

 Brazil. It might easily be mistaken for a variety 

 of corundum — Oriental topaz — or even quartz ; in 

 fact, it is highly probable that it is more abundant 

 than supposed, but has been overlooked from its 

 resemblance to the minerals mentioned. Some 

 minute bright green specks in granite from Ring- 

 arooma are probably the same mineral. 



67 Stilbite. — (Hydrous sodium, calcium, and aluminium 



silicate.) 

 In large radiating masses of a yellow-brown colour 

 imbedded in basalt vitrophyre. Bell Mount, 

 Middlesex. 



68 Strigovite. — (A basic silicate of iron and aluminium:) 

 A chlorite-like mineral consisting of a black shining 



aggregate of minute plates, in the fractures decom- 

 posed to brown. Occurs as a narrow band a few 

 inches wide in granite — near the Great Republic 

 Tin Mine. Ben Lomond. 



69 Stromeyerite. — (Sulphide of copper and silver.) 

 Analysis of an amorphous slug from the Mt. Lyell 



Mine : — 



Ag = 13-80 = 4507 ozs. 19 dwts. 23 s^rs. per ton 



Pb = 1-60 



98-66 



