198 THE MINERALS OF TASMANIA. 



341. Weldite (Silicate of Aluminium and Soda). 



"Amorphous; under the microscope, cryptocrystalline ; 

 optically negative; H = 5'5 ; G = 2*98. Lustre, vitreous 

 or pearly, opaque, white ; in thin splinters, subtranslucent ; 

 tough; fracture even. Comp-silicate of alumina and soda, 

 with traces of lime and ammonia. Before blowpipe fuses 

 at 3 with intumescence to a blebby glass. From the 

 unequal distribution of free silica and the presence of 

 ammonia, it is probable that the substance is the product 

 of transmutation of a felsitic or kaolinitic rock. If it can 

 be shown from its mode of occurrence that it is not merely 

 an altered rock, then it is undoubtedly a new mineral 

 species, to which the appropriate name of weldite might 

 be given. (Note by Professor F. M. Krause, of the Bal- 

 larat School of Mines, in the Proceedings of the Royal 

 Society of Tasmania, 1884.) 



Locality: Weld River, Upper Huon (C. Glover). Mr. 

 F. Stephens states '' It may be described as a massive 

 band interstratified with bands of quartzite and other 

 altered rocks ; and Mr. Glover has traced it for a mile in 

 the direction of its strike " (loc. cif.). 



342. WiLLEMiTE (Anhydrous Silicate of Zinc). 



Obtained in small compact patches, yellow-brown colour 

 and dull lustre. Bell's Reward, Whyte River, and at the 

 Heazlewood Silver-lead Mine, Heazlewood River. 



This mineral belongs to the hexagonal system, but is only 

 known to occur in this island in the amorphous form. 



343. WuLFENiTE (Molyhdate of Lead). 



A somewhat rare salt of lead. It crystallises in the 

 tetragonal system, but affects thin tables, which are often 

 extremely so and quite clear. It varies much in colour, 

 being often bright orange-yellow, or again brown, and 

 occasionally green. 



" Occurs, though rarely, in the lode of the Hampshire 

 Hills Silver Mine, associated with very fine-grained galena 

 and sphalerite. The crystals are of a brownish-yellow 

 colour, and square, thin, tabular, with rounded basal plane, 

 and hemihedral planes of the octagonal prism are dis- 

 tinctly recognisable round the edges." (TJlrich.) 



344. Wolframite (Tungstate of Iron and Manr/anese). 



This mineral crystallises in the monoclinic system, 

 although its common mode of occurrence is in the massive 



