BY W. F. PETTERD, C.M.Z.S. 135 



are usually from J-inch to 2 inches in thickness. One 

 peculiarity is that it is in all instances coated with a 

 somewhat thick varnish-like film of zaratite : another is 

 that it is highly magnetic. So far as is known, no 

 full analysis has been made of this mineral, but the result 

 of numerous assays distinctly shows that it is very rich 

 in Ni. Some of these t-ests have given a return as high as 

 38 per cent. The normal beyrichite is lead-grey in colour ; 

 specific gravity, 4*7; hardness, 3 to 3"5. Pentlandit^ has 

 about the same hardness and specific gravity, but the 

 usual colour is bronze, with, a bronze-brown streak. So 

 far heazlewoodite appears to be confined to the locality 

 above given, the Ni ores of the Dundas district belonging 

 to distinct minerals. 



237. Perovskite (Titanate of Calcium). 



This somewhat rare mineral occurs microscopically in 

 the melilite-nepheline basalt of the Shannon Tier, as 

 grains and small crystals of a yellowish-red colour. It is 

 developed in the nepheline-eudialite basalt of the same 

 locality in larger forms and without crystallographic 

 boundaries. Dr. Paul states that it often enwraps other 

 minerals, including eudialite in wreathed aggregates. 



238. Phacolite (Hydrated Silicate of Aluminium and 



Calcium). 



This is a variety of the zeolitic mineral chabasite, which 

 occurs in modified crystals of lenticular form. It is 

 abundant in basalt rocks. It occurs in plenty in the 

 vesicles of the Tertiary basalt at Waratah. Hellyer River, 

 Lefroy, Sheffield, Springfield, and Middlesex. 



239. Pharmacosiderite (^Arsenate of Iron). 



The primary form of crystallisation of this mineral is 

 the cube, by which character it may be separated from 

 scorodite, which is rhombic. It ranges in colour from 

 shades of olive-green to brown. It is ^ectile and resinous. 

 It occurs in some of the auriferous reefs of the Fingal 

 district in drnsy coatings of minute cubes of a grass-green 

 colour, generally in hollows of quartz rich in arsenopyrite. 

 The little cubes often show tetrahedral truncations of the 

 corners. Also at Waterhouse in the quartz reefs, and at 

 the Magnet Mine in coatings of microscopic crystals of a 

 green colour, and bright lustre in the vesicular ferro- 

 manganese gossan capping the lode. 



