MINER ALOGICAL NOTES : No. TIL— RHODONITE, 

 BROKEN HILL, NEW SOUTH WALES. 



By C. Anderson, ]\LA., D.Sc. (Edin.), Mineralogist, 

 (Plates xxviii-xxix.). 



Fine specimens of rhodonite are found in the sulphide zone of 

 the Broken Hill silver-lead mines, associated with galena, blende 

 and garnet, The occurence seems to have been Hist noted by 

 Professor R. Beck of Freiberg, by whom it has been described. 1 

 It is found either as crystals with the characteristic rounded edges 

 of rhodonite, or as isolated fragments disseminated through the 

 ore ; it generally shows evidence of corrosion by the metalliferous 

 solutions, and various stages of replacement by galena and blende 

 may be traced. The mineral is of a pleasing deep red colour, 

 and in small well crystallised specimens is quite transparent ; it 

 greatly resembles some varieties of garnet. 



Of the seven specimens which form the subject matter of this 

 paper three were kindly lent by the Director of the National 

 Museum, Melbourne, one by the Geological Department of 

 Sydney University, the others are from the Australian Museum 

 collection. 



Five crystals (referred to hereafter as Nos. i.-v.) were measured 

 on the two-circle goniometer and the co-ordinate angles obtained; 

 a few interfacial angles were also determined The position 

 chosen is that of Goldschmidt,- which, for rhodonite considered 

 by itself, and particularly for the usual habit of the Broken Hill 

 crystals, is more suitable than Dana's/ 3 as the three most promi- 

 nent faces, which are also the directions of cleavage, are made 

 axial planes, but Dana's elements show more clearly the relation 

 of rhodonite to the other members of the pyroxene group. 



In habit the crystals vary somewhat, but they may be generally 

 described as extended parallel to c (010). ' The commonest forms 

 are a (001), c(010), 6(100), o(110), s(110), the three first being 

 particularly well developed. In all twenty-eight forms were 

 recognised, of which ten are new, or at least not recorded in 

 Goldschmidt's ' Winkeltabellen.' The new faces occur principally 



1 Beck — Zeits. prakt. Geol., March, 1899, pp. 65-71 (trans. Kec. Geol. 

 Surv. N.S. Wales, vii., 1, 1900, pp. 20-28). 



2 Goldschmidt — Krystallographische Winkeltabellen, p. 2S7. 



3 Dana— System of Mineralogy, 6th Edition, 1S92, p. 37S. 



