83 



carl)onates of iron and manganese (949). Calamine also occurs Case 71. 

 in the Bredbo district (944, 945.) 7690, Broken Hill, a car- 

 bonate of zinc and lime ; it has been named ruleite. 



Sulj)hide of zinc ; of common occurrence in mineral veins. Blende 

 "When in deposits of considerable purity it is a valuable mineral — 

 such deposits are not as yet known to exist in New South "Wales. 

 The occurrence of blende in ores of gold or silver, gives rise to 

 much difficulty in treating them (see page 43.) Blende may 

 exhibit any shade of colour from amber to black ; but notwith- 

 standing this variability, it may be readily recognised by its 

 appearance after some practice. Blende is easily scratched with 

 a knife, the streak being usually buff in colour ; the mineral, 

 morever, has a jDeculiar resinous feel under the knife : both 

 characteristics are of great value in determination. Good 

 crystals are not common ; the best from this State are perhaps 

 those from Spring Creek, Bungonia, (2822, 952), v/here pale- 

 oloared varieties are sometimes found, and White Eock, Drake 

 (5965). 



Some A^arieties of blende contain a good deal of iron ; cadmium 

 is also sometimes present. 9559, Conrad Mine, Bora Creek, 

 contains 22i^ per cent, of iron, and a little cadmium.* 



COBALT. 



The consumption of cobalt in the Arts is not very great; 



nevertheless, the ores of the metal are of considerable value. 



Although cobalt minerals are comparatively rare, there is a 



considerable variety of them. For other ores see case 89. 



Aslolan : hydrous oxide of manganese containing a variable Col)altiferoiis 

 amount of cobalt; the principal cobalt ore in Australasia. This ^^ " 

 ore is found in irregular deposits in serpentine at Port Mac- 

 quarie, from which district several specimens, accompanied by 

 complete analyses, are exhibited ; and a block specimen in the 

 end compartment of case 51, The contents of metallic cobalt 



* The cadnihim of commerce is obtained from blende. When present in small quantities 

 it is said to be deleterious. 



