DETERMINATION OF MINERALS. 381 



the blowpipe prbduces no trace of fusion, but a brilliant 

 light from the fragment before it, but little doubt remains 

 on this point. Crystalline fragments of calcite break with 

 three equal oblique cleavages. 



Familiarized with these two Protean minerals by the 

 trials here alluded to, the student has already surmounted 

 the principal difficulties in the way of future progress. 

 Frequently the young beginner, who has devoted some 

 time to collecting all' the different colored stones in his 

 neighborhood, on presenting them for names to some prac- 

 tised mineralogist, is a little disappointed to learn that, 

 with two or three exceptions, his large variety includes 

 nothing but limestone and quartz. He is perhaps gratified, 

 however, at being told that he may call this specimen yel- 

 low jasper, that reel jasper, another flint, and another horn- 

 stone, others chert, granular quartz, ferruginous quartz, 

 chalcedony, prase, smoky quartz, greasy quartz, milky 

 quartz, agate, plasma, hyaline quartz, quartz crystal, basa- 

 nite, radiated quartz, tabular quartz, etc., etc.; and it is 

 often the case, in this state of his knowledge, that he is 

 best pleased with some treatise on the science in which 

 all these various stones are treated with as much promi- 

 nence as if actually distinct species ; being loth to receive 

 the unwelcome truth, that his whole extensive cabinet con- 

 tains only one mineral. But the mineralogical student has 

 already made good progress when this truth is freely ad- 

 mitted, and quartz and limestone, in all their varieties, 

 have become known to him. 



The student should be familiar with the use of the blow- 

 pipe and the reactions, as explained on pages 82 and 85 ; 

 and it would be still better if a fuller treatise on the subject 

 had been carefully studied. He should be supplied with the 

 three acids in glass-stoppered bottles ; a fourth bottle con- 

 taining hydrochloric acid diluted one-half with water, for 

 obtaining effervescence with carbonates ; test tubes ; and 

 also the ordinary blowpipe apparatus and tests, including 

 platinum wire, platinum forceps, glass tube, " cobalt solu- 

 tion," litmus and turmeric paper, etc. 



Also the following : 



A small file, three-cornered or flat, for testing hardness. 



A knife with a pointed blade of good steel, for trying 

 hardness. It may be magnetized, to be used as a magnet, 

 though a good horseshoe magnet of small size is better. 



