118 THE MINERALS OF TASMANIA. 



to siskin-gr€€n. Before the blowpipe in salt of phosphorus 

 it remains green when cold after both flames. In closed 

 tube with splinter of charcoal and heated intensely it gives 

 very strong and characteristic reactions for As O 4 ; with 

 cupric oxide gives flame reactions for CI, and in closed tube 

 with magnesium wire the odour of P'-O 5 It is reduced to 

 metallic lead with soda on coal. This is a variety suffi- 

 ciently distinct in composition, colour, and habit to be 

 worthy of record. It is rarely met with at its only known 

 locality, and then in comparatively small groups of crystals, 

 but its peculiar colourization, combined with the habit of 

 usually occurring in thin plates, at once arrests attention. 

 The chemical reactions show that it is more allied to 

 mimetite than to pyromorphite, a chromiferous variety of 

 which has been recorded. Locality : The Magnet Mine, 

 attached to the gossan in the superficial workings. 



Variety — Petterdite. (Twelvetrees, Pro. Roy. Soc. Tas, 



1901.) 



It has been shown by Dr. C. Anderson that this pre- 

 sumed new mineral species is but a crystallographic variety 

 of mimetite (Anderson, '' Records of the Australian 

 Museum," Vol. VI., Part 3). Referring to the crystals 

 the writer states, loc. cit., " Three crystals, each almost 

 4 mm. in diameter, were measured in a two-circle gonio- 

 meter. The angles obtained are only approximate, as the 

 faces are interrupted, wavy, and slightly curved, usually 

 yielding only a vague patch of light in the telescope. The 

 basal plane is rough, and gives no reflection ; therefore the 

 crystals were centred by the prism faces. The system is 

 hexagonal, the forms present being G (0001) and (1121). 

 Pyramidal faces do not occur in all the crystals, and the 

 pyramid (1011) is the commoner and better-developed. 

 From the measurement 0001 a 1011 = 38^ 42', the length 

 of the vertical axis was found to be '69 38. The measure- 

 ment angle 0001 A 1121 is 53° 20', calculated 54° 13'." 



Occurs in the form of somewhat thin hexagonal plates 

 or crystals, which are usually about 5 mm. in diameter, 

 but occasionally up to 9 mm., and still more rarely of a 

 large size. The colour is white, passing to a pale-grey on 

 the surface. Locality : The Britannia Mine, Zeehan. 



•209. Mineral Pitch. (See Asphaltum.) 



210. Minium (Red Oxide of Lead). 



Occurs as a pulverulent coating on other lead minerals 

 and lode-matter. The colour is an unmistakable bright-red, 



