200 THE MINERALS OF TASMANIA. 



lions. In this mine they accompany, besides the usual 

 quartz, small topaz crystals, with cassiterite, bismuth (sul- 

 phide and carbonate), fluor and talcose spodumene. At 

 the mineral section originally known as the Mt. Black 

 Prospecting Association, at Mt. Dundas, it occurs in small 

 patches in a dense mass of fluorspar and chalcopyrite, with, 

 more rarely, blades of bismuthinite, and intensely black 

 radiating bunches of tourmaline. 



About 1 mile a little east of south of the Mayne's Tin 

 Mine, at Heemskirk, on the extreme west, a very interest- 

 ing find of partially pseudomorphous wolframite has been 

 made. The crystals of the original mineral are extremely 

 well-formed, of the normal character, and fairly large in 

 size. The whole mass of the crystals is more or less altered 

 to scheelite. Sometimes the planes are faced by a thin 

 layer of the tungstate of lime of a glistening pale-yellow 

 colour, and more rarely one-half of the crystal will appear 

 to be thus transmuted. At the Bischoff Mine, wolframite 

 is remarkably rare, and when found it is in but compara- 

 tively small patches attached to the topaz-porphyry so 

 characteristic of the mine. It is stated by the late Pro- 

 fessor XJlrich to occur pretty frequently in the West Bis- 

 choff tin lode in aggregations of rather ill-developed 

 crystals, also impregnated in small patches and irregular 

 grains. The matrix is generally quartz, but sometimes an 

 intimate mixture of apatite and topaz occurs, and in hol- 

 lows of such specimens the rare mineral monazite is found. 



At Storey's Creek and other places in the vicinity on 

 Ben Lomond a considerable quantity has been mined and 

 exported. It occurs with cassiterite, with quartz, in some- 

 what altered granite impregnated with white muscovite 

 mica. Other localities are the Ethel Mine, Blue Tier; 

 North Pieman River, near the coast; Black Bluff Mount- 

 ain ; Mt. Thomas, near Mt. Claude ; Great Mussel Hoe 

 River ; Mt. Rex Tin Mine ; and other places of less 

 importance. 



345 WoLLASTONiTE (Silicate of Calcium). 



Also known as '' tabular spar." It is doubtfully referred 

 to the pyroxene group. It belongs to the monoclinic 

 system of crystallisation, and is common to metamorphic 

 limestone formations, and in regions of granite, as a con- 

 stant alteration. It occurs at Highwood, south of the 

 Hampshire Hills, where it apparently gradually merges 

 into a crystalline rock much resembling a variety of 

 diallage. Here it is white and granular, with individual 



