25 



with caloife, fabl-ore and antimnnite. The oxidalion of the Case 48- 



fahl-ore gives rise to staiuings of carbouate of copper in the 



upper levels (6283). Ihe country rock is a hornblendic granite 



(6680). This is traversed by a belt of diorite (6637), and it is 



at the junction of the two rocks that the cinnabar-bearing veins 



occur. Cinnabar is also found in small quantities impregnating 



the surrounding rocks.* In thin sections under the microscope 



the cinnabar is seen scattered through the rocks in the form of 



microscopical specks. There is the clearest evidence that the 



cinnabar has been deposited from solution in water. In one 



microscope section a felspar crystal w^as seen to have had cinnabar 



deposited along the lines of cleavage. 9380 is a decomposed rock 



from near the surface ; ifc contains cinnabar deposited in it in. 



spots by permeating solutions. 6283 is from a bunch of rich ore. 



6677 and 7014 respectively shovi^ calcite and fahl-ore (antimonial 



copper ore) ; and 9378 antimonite, associated with cinnabar. 



The silica of the vein-stuff is occasionally in the form of crystalline 



quartz (6283), but is generally in a more or less cherty condition 



(6678 and others), 



BroJcen Hill. — Small quantities of mercury have been found 

 in the Broken Hill mines, in combination with icdine. These 

 compounds are of a beautiful red colour when found, but rapidly 

 fade on exposure to light ; for this reason the specimens are kept 

 covered. 7451 is of special interest, having been formed in the 

 mine-workings of the Proprietary Mine, in consequence of the 

 lire there a few years ago. 1263, from the Consols Mine, is 

 associated with iodide of silver. 



Mercury ores from other countries will be found in case 77. 



GOLD. 



The collection of New South Wales gold ores is contained in Case 50. 

 cases 50-57. It should be studied from right to left, beginning 

 with number 50. The series comprises crystallised gold, alluvial 



* Cinnabar is a very powerful pig'ment (vermilion of commerce), a minute percentage 

 disseminated through a rock being sufficient to produce a pronounced colouration, thereby 

 giving rise to a deceptive idea of the richness of the ore. Thus the vein in 9379 is not 

 nearly so rich as it looks, consisting largel3' of stained quartz. 



