BY W. F. PETTERD, C.M.zS. 67 



The Fe.:; and O.,, or a portion thereof, may be foreign 

 to the substance, as it is next to impossible to perfectly 

 separate it, since it almost invariably occurs as an incrusta- 

 tion on the mineral from the original locality at Dundas. 

 A trace of Po O3 was also found; this was certainly 

 obtained from an extremely thin coating or skin of pyro- 

 morphite, which is often present, and gives an external 

 green colouration to the surface of the mineral. At the 

 Hercules Mine, Mt. Read, a mass of snow-white cellular 

 quartz has been obtained, throughout which are scattered 

 crystals of cerrusite, gibbsite, and numerous patches of 

 dundasite, the whole forming one of the most attractive 

 associations of minerals as yet obtained in this State. 



Referred to in Dana, " First Appendix to the Sixth 

 Edition of the System of Mineralogy," page 23. 



This mineral has been more recently found at the West 

 Foxdale Mine, Trefriw, Carnarvonshire, Wales, by Mr. 

 H. T. Collins (G. T. Prior, Mineralogical Society, 1905, and 

 " Nature," April 13, 1905). Thus we have the novelty 

 of a new Tasmanian mineral being subsequently discovered 

 and recognised in Wales. 



112. Elaeolite ( Orthosilicate of Sodium, Potassium, and 



Aluminium). 



The coarse massive form of nepheline. It is compact, 

 with a greasy lustre. It occurs as an essential of several of 

 the alkaline rocks of Port Cygnet. 



113. Embolite (Chlorohromidc of Silver). 



Found in limited quantity, but at times quite pure. As 

 is usually the case, well-formed crystals are difficult to 

 obtain, but moderately good specimens are not rare. 

 Occurs intermixed with ferro-manganese gossan and earthy 

 lode-matter. The more important localities are the follow- 

 ing mines: — Central Dundas and West Comet at Dundas; 

 the Queen, Sylvest-er, and Junction at Zeehan ; the Godkin. 

 Washington Hay, and Whyte River in the Heazlewood 

 district ; and the Beulah at Scamander River. 



Embolite merges gradually into cerargyrite, the two 

 species being isomorphous. The mixtures occur both here 

 and in Australia in varied proportions, so that the one 

 species may gradually merge into the other. In minute 

 but perfectly cubical crystals, which are occasionally octa- 

 hedra. It occurs in an irregular seam of gossan at the 

 Magnet Silver Mine, Magnet. 



