148 THE MINERALS OF TASMANIA. 



270. Pyrrhotite (Sulphide of Iron). 



Also known as magnetic pyrites. It crystallises in the 

 hexagonal system, but the crystals are extremely rare. 

 The only known occurrence of the crystals in this island is 

 at the Colebrook, North-East Dundas, where they occur 

 of the usual diminutive size, in small clusters on the parent 

 mineral. The amorphous substance also occurs at this 

 locality in immense quantity in close association with axin- 

 ite and a little arsenopyrite, datolite, and chalcopyrite. The 

 pyrrhotite is of the usual bronze colour, with a noticeable 

 tarnish of the brighest shades of red, blue, and green, which 

 gives it the pseudo appearance of being an ore rich in 

 copper. Occurs as a large massive formation near George's 

 Bay ; at Mt. Ramsay in amphibole rock, with native bis- 

 muth and other minerals; in main adit at Mt. Bischoff the 

 samples weather to a normal bronze lustre ; at Hampshire 

 in amorphous masses, which have a decided red tinge, and 

 also of a grey colour, disseminated in a hard metamorphic 

 rock; Penguin River, where it is highly nickeliferous ; 

 Dundas, said also to carry nickel ; samples from the Blue 

 Tier, near Beaconsfield, have been found to contain nickel, 

 and in the old adits the mineral has decomposed to a 

 mixed sulphate of that metal and iron ; Beaconsfield, 

 where it is often auriferous ; Mt, Pelion, in enormous 

 masses ; Rocky River and Savage River, in considerable 

 quantities; Barn Bluff, with actinolite and pyrites. 



271. Quartz (Silica). 



This abundant and widely diffused mineral is common 

 both in the amorphous and crystallised form. The crys- 

 tals occur as hexagonal prisms, which sometimes have 

 pyramidal terminations at both ends. It is found in 

 many parts of the island, often in considerable abundance. 

 The crystallised form more especially is met with in pro- 

 fusion in the tin-mining districts, where examples of large 

 size, more or less waterworn, and showing a wide range of 

 colouration, form one of the main features of the stan- 

 niferous drift. On Flinders Island and in the vicinity of 

 Mt. Cameron individual crystals weighing many pounds 

 are commonly obtained. They are known as " rock- 

 crystal," and are beautiful representations of the species. 

 In the auriferous districts the quartz is usually more or 

 less milky-white owing to enclosed vesicles, but extremely 

 fine bunches of clear colourless crystals have been obtained 

 at several localities. At the Heazlewood, quartz, often 

 coloured green with the oxide of chrome, is an abundant 



