:3U 



PKOCEEUIXGS OF SECTION C. 



piously been recorded in Australia an incomplete analysis of it was 

 submitted to you. The analysis has since been completed, the final 

 results being : — 



Microlite, Wodgina. 



Tantalum pen toxide ... ... ... 73 'SI 



Niobium pentoxide ... ... ... 3"62 



Tin dioxide "90 



Lime 1346 



Magnesia ... ... ... ... ■-42 



Iron protoxide ... ... ... 3 64: 



Manganese protoxide ... ... '60 



Potash -20 



Soda ... ■ 1-66 



lo'nition loss ... ... ... ... r28 



99-32 



Sp. gr. 5'422 



No traces of ceria or ji:tria were detected in it. 



Another interesting mineral has recently been received from the 

 Wodgina district. It occurs in a veiy fresh state in a matrix of 

 gi anular albite, the latter with a little quartz and muscovit© forming 

 about 72 per cent, of the ore. The remaining 28 per cent, consists of 

 a tantalate with a somewhat resinous lustre, and varying in colour 

 fjom pale cinnamon brown to dark brown. It occurs in indistinct 

 crystalline aggregates, the system of which has not been determined. 

 In thin slices it is subtransparent, and apparently homogeneous except 

 for gradual slight variations in the depth of colour, which apparently 

 deepens under alteration along cleavages, &c. Cai"efully selected 

 material was analysed with the following results : — 



Ir/ioJite ( ?/, Wodgina. 



Sp. gr 7-36 



If the tin is present in combination this yields a formula — 



3MnO.3Ta2O5.SnO2. 

 In the large proportion of tin oxide and in the bglit brown colour of 

 the powder it resembles the ixiolite of Nordenskiold (Kassiterotantal 

 of Hausmann), until, however, its crystallographic system has been 

 determined and its apparent uniformity in tin contents confirmed, its 



