BY \V. F. PETTERD. 81 



21 Pyrostilpinite. — (Silver sulphant nn omf e .) 



A rare ore of silver (containing 59.44 per cent, of 

 ag) known as 'fire-blende." It crystallises in the 

 monoclinic system and is sometimes tabular, but 

 its common habit is in imperfectly terminated 

 sheaves or irregular bunches— like stylbite — but 

 of almost microscopic dimensions. It is of a 

 hyacinthrred colour, but is generally tarnished to 

 an almost black discolouration. When free from 

 discolouration it has an adamantine lustre and 

 decided red streak. In minute vughs it may be 

 detected in association with nests of small quartz 

 crystals. When coating cleavages in its extremely 

 silicious gangue it soon arrests attention by its 

 peculiar habit of occurrence in radiating and 

 irregular bunches, by which feature it may be 

 known from proustite, although both have the 

 same bright colour. Before the blow-pipe it 

 fuses easily, giving off white antimonial fumes, 

 and wath soda affords a bead of siWer. It occurs 

 in limited quantity, but quite enough to make 

 an appreciable difference in the bulk silver 

 assays. Locality, the Long Tunnel Mine, Heazle- 

 wood. Associated with this is another silver 

 mineral of an orange yellow colour with yellow 

 streak. It affects a frondose habit, and is found 

 in exceedingly limited quantity as aggregates 

 in the cleavages of the gangue. It may be 

 xanthoconite (a silver sulpharsenate, crystallis- 

 ing in the rhombohedral system), but the quantity 

 is too small to make reasonably certain of its 

 exact identification. 



22 Quartz.— (*S'^7^cor^ dioxide.) 



Mr. D. A. Porter, of Tamworth, N.S.W.,has recently 

 drawn my attention to an interesting occurrence 

 of this mineral in a specimen associated with 

 freibergite. Many of the extremely minute 

 crystals attached thereto are ''left handed" and 

 others "right handed," and many of these show 

 besides the "W" and ''Y" trapezoids the rhombic 

 face ''S." This habit has not been detected in 

 larger crystals from the same locality. The Her- 

 cules Mine, Mt. Read. 



28 ScoRODiTE. — {Hydrous ferric iron arsenate.) 



This mineral was obtained by Mr. W. R. Bell in 

 clusters of beautifully formed orthorhombic 



