132 GUIDE TO THE AUSTRALIAN MUSEUM. 



The minerals which do not exhibit a metallic lustre are divided 

 into three groups. The first includes minerals which burn or 

 volatilize easily under the blowpipe, such as Sulphur, Cinnabar, 

 Oxide of Antimony, &c. The second includes minerals which 

 melt more or less easily, but do not disappear by volatili- 

 zation under ordinary circumstances, such as Chloride of Silver, 

 Carbonate of Lead, Malachite, Garnet, Tourmaline, &c. The 

 third includes minerals which are infusible or only fusible 

 with difficulty, such as Quartz and many silicates and gems, 

 some Iron ores, many earthy minerals, Limestone, Chrome ore, 

 Pitchblende, Tin ore, Zincblende, Nickel ore (Garnierite), &c. 

 Some of them appear in two groups. 



The scale of fusibility affords some means of comparison, and 

 the degree of fusibility is expressed by a number It is arranged 

 as follows : — 



1. Stibnite. Fuses easily in the candle flame, 



2. Natrolite. Fuses in the candle flame. 



3. Almandine Garnet. Fuses easily before the blowpipe. 



4. Actinolite, a varietv of Hornblende. Fuses more or 



less easily before the blowpipe when in minute 

 fragments. 



5. Adularia. A variety of Orthoclase. 



6. Bronzite. Small fragments are only rounded on the 



edges before the blowpipe. 



7. Quartz. Infusible in ordinary blowpipe flame. 



Vir.— COLLECTION ILLUSTEATING DYNAMICAL 



GEOLOGY. 



This collection, though but recently commenced, is one that 

 will commend itself to the student and miner. It is 

 difficult to trace strict divisions, but, broadly speaking, there are 

 phenomena taking place both on the surface and at various depths, 

 which are rather to be classed as mechanical than otherwise, and 

 there are phenomena in which chemical actions are predominant. 



Among the results of mechanical action, examples are exhibited 

 illustrating the effects of such pressures as cause the cleavages of 

 rocks, the wedged ends of faulted reefs, &c., the results of earth 

 movements in metalliferous lodes. 



