40 



Case 5 J* Of the Gundagal exhibits the series from the Prince of Wales 



Mine is of special interest from the association of tellurides of 

 bismuth with the free gold, and particularly because the existence 

 of telluride of gold has been detected (9035j, though not iu 

 tangible grains. The stone consists of white quartz of a more 

 or less milky character, sometimes associated with copper ores. 

 Telluride of bismuth (9035) appears in platy grains of. a steely 

 or tin-white colour. Analysis has shown that lead enters into 

 the composition of the mineral, which would therefore not be 

 true tetradymite, and may be an undesoribed species. Glass 

 ifilips showing metallic tellurium, separated from the ore by 

 -chemical means, are placed with 9035 In case 109 is a block of 

 slate (8001) traversed by a vein of gold-bearing quartz from this 

 mine. 



5773, 63.25, Gundagai, are further instances of gold on slate. 

 In every case yet referred to in this guide (see pages 30, 31, 33), 

 the gold has been found coating the cleavage faces of the slate ; 

 in this instance, however, it is found abundantly on an uneven 

 joint-face. 



Yet another interesting exhibit from Gundagai is fibrous 

 serpentine (picrollte) coated with filmy gold — 2225, 6931. Such 

 specimens are very difficult to preserve, as the gold so readily 

 becomes detached. 



2159, Cubes of pyrites, with an outer layer of linionite (see 

 p. 26). The limonite is coated with free gold. 



Several specimens of mica-slate showing gold, from the neigh- 

 bourhood of Albury, will be noticed. The rock was most pro- 

 bably originally a clay-slate, but has been metamorphosed (5775 

 and others). 



Cise 57. ■ ■^(f^^o'^'J^ Murrumhitrrah. — As at Timbarra, the country rock 

 at Adelong is granite, which is sometimes itself auriferous, — 

 (6538)— Chlorite schist (6540) also occurs. 9473 from the 

 Challenger Mine illustrates in miniature the occurrence of the 

 ore-bodies. The rock is a fine-grained granite and contains 

 lenticles of quartz connected by strings of the same mineral 



