BY W. F. PETTERD, C.M.Z.S. 49 



78. Chonicrite (Hydrated Silicate of Calcium, Mag- 



nesiu7n, and Aluminium). 



This is a substance with much the general appearance 

 of ordinary chlorite, to which group it apparently belongs. 

 In structure it is radiating, with a silky lustre, and is 

 lavender-blue in colour. It is always accompanied by fine 

 gi'anular quartz. Several specimens were obtained as loose 

 boulders ; it has not been found in situ. 



Locality : A tributary of the Rocky River, which stream 

 falls into the Pieman. 



79. Chromite (Oxides of Chromium and Iron). 



This mineral is apparently widely distributed through- 

 out the north-western portion of the island, but has not 

 been recorded as occurring in large quantity. It is always 

 to be found in more or less profusion wherever serpentine 

 occurs, sometimes intermixed with that rock in the form of 

 minute crystals, but more often as irregular patches '^f 

 various sizes, which occasionally form somewhat extensive 

 masses. At the Heazlewood it is fairly abundant in the 

 massive form, but not, so far as exploited, in large quan- 

 tities. Occurs in crystalline masses in a small vein occur- 

 ring between serpentine and quartz, near the River Forth ; 

 at Harmon's Rivulet, Huskisson River, as small crystals as 

 well as massive ; Dundas, in limited quantity ; plentiful 

 in the bed of the Arthur River, below its junction with the 

 Waratah River ; in the serpentine at Anderson's Creek, 

 Forth River, Styx River, and the head of the Florentine. 



80. Chrysoberyl (Aluminate of Beryllium ). 



Variety — Alexandrite. 



A remarkably fine example, with a few of indifferent 

 character, of this highly-prized gem-stone was obtained by 

 Mr. J. A. Thomson at the Weld River, in stanniferous 

 drift, during the ordinary process of dressing tin ore. It 

 is of a somewhat pale but attractive green colour, red h^ 

 transmitted light, as is characteristic of the variety. It 

 was, by the kindness of Mr. Thomson, tested with the 

 dichroiscope by Mr. W. H. Twelvetrees, Government 

 Geologist, with the result that its identification was placed 

 beyond doubt. It is remarkable that this is the first cut 

 specimen which has come under notice. In all probability 

 this gem has been looked upon as a pale transparent corun- 



