GENERAL CHARACTERS OF MINERALS. Ill 



5. Ascertain in what respects quartz differs from crystal- 

 lised carbonate of liine, and what are its best distinguishing 

 characters. 



6. Describe carbonate of lime under the heads specified 

 above, and repeat in what particulars it is distinguishable 

 from quartz. 



7. Describe, in a similar manner, hornstone and feldspar, 

 and state the points of distinction between such varieties of 

 these substances as resemble each other. 



8. Describe augite and hornblende, and state their dis- 

 tinctive characters. 



9. Pay particular attention to the following mineral sub- 

 stances, as being of frequent geological occurrence, viz., mica, 

 talc, clinkstone, claystone, chlorite, actinolite, hypersthene, 

 diallage, serpentine, steatite, jasper, porphyry, basalt, carbo- 

 nate of magnesia, bitterspar, dolomite, sulphate of lime, 

 bitumen, oxide of iron, sulphuret of iron, iron and copper 

 pyrites, schorl, garnet, and chiastolite. 



10. Commit to memory the names of those minerals which 

 represent the scale of hardness. 



11. Select various sets, comprising each some half-dozen 

 familiar substances, and describe their principal characters, 

 as primary form, fracture, colour, transparency, hardness, 

 action of acids, action of blowpipe, &c. &c. 



12. "Write out a list of crystalline forms, and copy, on 

 tracing paper, the outlines of such as are most familiar and 

 of frequent occurrence. 



13. Copy and commit to memory a list of the zeolites, 

 enumerating their principal varieties and distinctive cha- 

 racters. 



14. In exemplifying the above instances, the student 

 should be careful to unite practice with theory, and to com- 

 pare every substance with specimens from his own cabinet, 

 with the view to realise the features of the descriptions which 

 he finds in books. 



15. After a short period, he may place before himself a 

 drawer filled with various but allied species of minerals, and 

 endeavour to ascertain the names and characters of each. 



16. "When further advanced, he may place before himself 

 a collection of heterogeneous kinds and endeavour to iden- 

 tify their names and varieties. 



