the minerals of new south wales. 177 



Galena. 



Chem. comp.: Lead sulphide = PbS. Lead, 86*6 ; sulphur, 13*4 

 = 100. This, as elsewhere, is the commonest ore of lead ; it not 

 only occurs in large deposits, but it is widely distributed over the 

 Colony. 



It is usually found in the massive state, and with a granular 

 structure which varies from fine to coarse. Occasionally it is met 

 with fairly well crystallized, as at Cambalong, but on the whole 

 crystals are rare. In other respects it presents all the usual pro- 

 perties of the mineral as found in other countries. 



Localities — Near Inverell, and other places in New England ; 

 at Talwal Creek, on Yalwal Water ; Reedy Creek ; Wallabadah ; 

 on the Peel ; the Page, Isis, and Hunter Rivers ; at Burrowa, in 

 quartz veins ; with copper ores, on Lawson's Creek, a tributary of 

 the Cudgegong ; at Gulgong ; Jugiong Creek ; Crook well River ; 

 Waroo, near Humewood ; near Bathurst ; Wellington ; Sandy 

 Swamp ; at Mylora Creek, near Yass, in a quartz porphyry ; at 

 Woolgarloo, in association with fluor spar ; near Bombala ; at 

 Kiandra, in quartz veins. 



In all cases the galena is more or less rich in silver. 



Tin. 



Cassiterite. 



Tinstone. Chem. comp: Tin binoxide = Sn0 2 . Tin, 78*67; 

 oxygen, 21-33 = 100. 



Tetragonal system. Occurs massive, crystallized, and as rolled 

 pebbles and masses known as " stream tin." Well-developed crys- 

 tals are by no means rare ; the forms assumed are very similar to 

 those found in other countries, viz., the prism, or a series of prisms 

 combined with the pyramid, or pyramids, with and without the basal 

 pinacoid plane. Sometimes the crystals are very large, especially 

 those which are made up solely of the planes of the pyramid. 



The lustre is usually bright metallic, hence many of the speci- 

 mens are exceedingly pretty and brilliant, especially some of the 

 ruby and amber coloured transparent specimens, which, however, 

 have not as a rule so high a lustre as the black crystals ; the colour 

 varies from almost colourless and transparent, through shades of 

 grey, yellow, amber, red, brown, to black, and opaque. Often more 

 than one of these colours are to be seen in the same specimen, 

 when the effect is very fine, especially the admixture of the ruby- 

 red and translucent amber colours. 



The hardness and sp. gr. do not appear to differ from tinstone 

 obtained elsewhere. 



The principal tin veins in New South Wales which have yet 

 been worked, occur in granite at once seen to be similar to 



