BY W. F. PETTERD, C.M.Z.S. 119 



with a feeble lustre. Locality : Whyte River Silver-lead 

 Mine. 



At the Adelaide Proprietary, Dundas, the cerussite 

 crystals are occasionally pitted with a dull black lead- 

 oxide, which may be this species discoloured with powdery 

 oxide of manganese, or it may prove to be its more rare 

 congener the binoxide (plattnerite). The minute quantity 

 noticed prevents a careful examination. 



Obtained as small encrusting patches of the usual bright- 

 red colour in the superficial workings of the Long Tunnel 

 Mine, Castray River. 



211. MiRABiLiTE. (See Glauber Salt.) 



212. MizzoNiTE (Chlorosilicate of Calcium and Alu- 



minium). 



A scapolifce, which occurs as small t-etragonal crystals^ 

 with the habit' of four-sided prisms. It is of a pale-brown 

 colour, and is translucent, with a distinct vitreous lustre. 

 The small crystals, which are somewhat irregularly grouped 

 together, forming thus a matted mass, are individually 

 divergent, and at times much intermixed. The crystals, 

 are elongated with distinct vertical striation. This min- 

 eral, as is not an unusual feature in the majority of the 

 members of the scapolite group, is specially and readily 

 liable to extreme alteration by decomposition, this when 

 well advanced assuming the form of a dull, chalky, white,, 

 almost powdery substance, which is attached to, and 

 encrusts in irregular patches, the matted crystals which 

 remain unaltered. The mass of the material containing^ 

 the mizzonite is usually in a very crumbling condition, 

 and is commonly discoloured by associated earthy matter 

 as well as by the oxides of manganese and iron. Locality : 

 North-East Dundas. 



The same species of mineral also occurs at the base of 

 Valentine's Peak, Upper Emu River. At this locality it 

 occurs mainly in the amorphous form, showing a granular 

 structure, with an occasional slight fibrous tendency. The 

 cavities or fractures are lined or coated with a thin layer 

 of small crystals, which are fairly well developed. The 

 crystals are irregularly interwoven, and of a very pale- 

 brown colour. 



The massive mineral is always of a somewhat pale colour, 

 varying from almost white to a light shade of brown ; more 

 rarely there are ill-defined seams and patches of a bluish 

 tint. It appears to be fairly abundant. 



