54 MINERALS AND GEOLOGY 



!Sp. gr. under 2.8 ; H = 7.0 ; vitreous ; fusible with carb-soda into a 

 clear glass QUARTZ (No. 43.) 

 Sp. gr. overS.0 63 



Harder than quartz 64 



Less hard than quartz 65 



ization, Hexagonal ; H = 9.0 : sp. gr. 3.8 4.1 Corundum 



(No. 41.) 



I Crystallization, Octahedral .(Regular System); H = 8.0 ; sp. gr... . 



fi4 ! 3,545... ...................................... Spinel (No. 4.) 



: j Cystallization, Square-pyramidal (Tetragonal System) ; H=7.5 ; sp. gr. 

 4.04.7 .......................................... Zircon (No. 44.) 



I Crystallization, Rectangular-prismatic; H = 7.0 7.5 ; sp. gr. 3.1 

 I 3.2 ............................................ Andalusite (No. 45. ) 



( Red or orange ; Lustre inclined to semi-metallic ; sp. gr. 4.1 4.3 ..... 



Rutile (No. 40.) 

 A) _ J Yellow ; in small granular masses (mostly with graphite in crystalline 



limestone); sp. gr. 3. 1 3.2 ..................... Condrodite (N T o. 56.) 



1 Green, brownish-yellow ; in crystalline grains in eruptive rocks ; sp. gr. 

 I 3.3 3.5 ....................................... Olivine (No. 55.) 



fifi ( Strongly magnetic ................. MAGNETIC IRON ORE (No. 31.) 



)D j Feebly (or non-) magnetic ........................................ 67 



Streak-powder, black or brown .................................... 68 



Streak-powder, pull-red ...... , ............ RED IRON ORE (No. 29. ) 



( BB, with borax, an emerald-green glass ____ CHROMIC IRON ORE (No. 33.) 

 j BB, with borax, a dingy-green glass. . . TITAN IFEROUS IRON ORE (No. 30.) 



fi q ( BB, fusible, or imparting distinct colour to the flame, or both ........ 70 



)y I BB, infusible (or fusible only at the external point) ................. 77 



BB, easily dissolved by borax or phosphor-salt, the saturated glass be- 



hen flamed (p. 

 BB, slowly and incompletely dissolved by borax or phosphor- salt, a 



coming opaque on cooling or when flamed (p. 37) .................. 71 



, slowly and incompletely dissolved by borax or phosphor- salt, a 

 " silica skeleton" (p. 39) separating in the latter reagent ........... 74 



-, ( BB, yielding sulphur-reaction with carb-soda and silver foil (p. 44) .... 72 

 | BB, no sulphur-reaction with carb-soda, &c. Mostly in cubical crystals . . 



FLUOR SPAR (No. 106.) 



! Yielding a large amount of water by ignition in bulb-tube ............. 

 GYPSUM (No. 9&) 

 No water on ignition ........................................... 73 



73 



BB, imparting an apple-green tint to the flame-border. Fusible with . 



difficulty. BARYTINE (No. 96.) 

 BB, imparting a carmine-red colour to the flame-border 



CELESTINE (No. 



- . ( BB, imparting a green tint to point of flame Datolite (No, 68. ) 



| BB, imparting a yellowish or indistinct colour to the flame ...... 75 



-- ( BB, fusible quietly Analcime (No. 75. ) 



10 ( BB, intumescing 76 



