^8 THE MINERALS OF TASMANIA. 



and flaky masses, varying in size from microscopic grains 

 to pieces weighing several ounces. It occurs associated 

 with blue and white fluor, scheelite, and axinite, with the 

 metallic minerals pyrrhotite, chalcopyrite, and pyrite. 

 The mass of hornblende occurs as a contact formation 

 abutting upon granite on the one side and an igneous 

 rock on the other. At Mt. Read this metal has been dis- 

 covered in quartz with fluor ; it has also been obtained at 

 the Blue Tier in granite, with cassiterite and molybdenite. 

 Some of the alluvial gold obtained at the Ring River is 

 said to contain this metal as an alloy ; it would therefore 

 approach the substance that has been named maldonite. 

 Although bismuth is commonly auriferous it is not so at 

 Mt. Ramsay ; the gold at that locality was obtained from 

 chalcopyrite and mispickel. Obtained as small waterworu 

 pieces Wilson's Creek, Pieman River; with cassiterite at 

 Middlesex. 



50. BiSMUTHiNiTE (THsulphide of Bismuth). 



This is also known as bismuth glance. It crystalli&es 

 in the orthorhombic system like stibnite, to which it is 

 chemically allied, and which it resembles in its physical 

 characters. It commonly affects a bladed habit ; the 

 crystals are prismatic, but usually acicular. These needle- 

 like forms are of a lead-gray colour with metallic lustre, 

 and brittle. Their surface is often tarnished. The 

 mineral has a perfect cleavage parallel to the blades ; the 

 surfaces thus formed are smooth and highly polished. In 

 somewhat rare instances the mineral assumes a capillary 

 form, the filaments being not infrequently interwoven 

 with the gangue minerals. Bismuthinite is in all proba- 

 bility an original mineral, but it is easily affected, and 

 commonly changes to the carbonate, oxide, or other second- 

 ary forms. It is a frequent accessory in tin lodes, and 

 often accompanies wolframite, molybdenite, and fluorite. 

 The frequent presence of the last-named suggests that 

 fluorine may have been an active agency in the deposition 

 of such minerals as those mentioned. It occurs in small 

 irregular patches with the native metal in the araphibolite 

 of Mt. Ramsay. It has been met with in the workings 

 of the Federal Tin Mine at Heemskirk, and in other mines 

 in the vicinity, and at the Blue Tier in the stanniferous 

 granite in small quantity. At the East Hercules it has 

 been met with in chlorite schist with pyrite and a little 

 fluorite. At the South C'urtin-Davis Mine, Dundas, and 

 others adjacent, it has been mined in some quantity, inti- 



