54 MINERALS AND GEOLOGY 



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



62 ! clear glass QUARTZ (No. 43.) 



Sp. gr. overS.0 63 



rq j Harder than quartz ' 64 



M / Less hard than quartz , 65 



{ Crystallization, Hexagonal ; H = 9.0 ; sp. gr. 3.8 4.1 Corundum 



(No. 41.) 

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



I 3,5_45 Spinel (No. 42.) 



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



4.04.7 Zircon (No. 44.) 



| 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.) 

 rp . J Yellow ; in small granular masses (mostly with graphite in crystalline 



limestone); sp. gr. 3. 1 3.2 Condrodite (N 7 o. 56. ) 



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

 I 3.3 3.5 Olivine (No. 55.) 



Strongly magnetic MAGNETIC IRON ORE (No. 31.) 



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.) 



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



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



J | BB, infusible (or fusible only at the external point) 77 



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



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



y BB, 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.) 



72 



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



i^-V 



GYPSUM (No. 98.) 



\ A JL JL kJ ^jf J.TA \ J-l \J. i/<J. / 



( No water on ignition 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. 96. ) 



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



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



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



/0 j BB, intumescing 76 





