DETERMINATION OF MINERALS. 395 



to a magnetic globule, after roasting gives reactions for nickel, 

 cobalt, and iron. 

 SPHALERITE, p. 154. H.=35-4 ; G.=39-4'2 ; isometric ; lustre 

 submetallic ; streak nearly uncolored ; nearly infusible alone and 

 with borax ; on coal a coating of zinc oxide. 



b. ARSENICAL FUMES, WITH OR WITHOUT SULPHUROUS. 



ARSENOFYRITE, p. 175. H.=5-6 ; G.=6-6'4 ; trimetric ; white, 

 gyb, streak dark gyb black. In closed tube, red arsenic sulphide 

 and metallic arsenic ; B.B. on coal fuses to magnetic globule. 



GERSDORFFITE, p. 166. H.=5 5 ; G.=5'o-6-9 ; isometric, py- 

 ritohedral ; white, gyh, streak grayish -black. In closed tube 

 arsenic sulphide, on coal not magnetic, and reacts for nickel and 

 often cobalt. 



NICCOLITE, p. 166. H.=5-55; G.=7-3-77; hexagonal; pale 

 copper-red, streak pale bnh black ; in open tube, coating of arsen- 

 ous acid ; B.B. on coal no sulph. fumes, fuses to globule which re- 

 acts for iron, cobalt and nickel. 



SMALTITE, p. 165. H.=55-6 ; G.=6^7 2 ; isometric ; tin-white ; 

 streak gyh black ; on coal, no fumes of sulphur or only in traces. 



2. NOT YIELDING FUMES OF ANY KIND. 

 STEEAK UNMETALLIC. 



A. B.B. EASILY FUSIBLE, AND GIVING A MAGNETIC BEAD. 

 LUSTRE SUBMETALLIC. 



ILVAITE, p. 263. H. =5-5-6; G. =8-7-4-2 ; trimetric; gyh iron- 

 black, streak gnh or bnh black ; gelat. with H CI. 



ALLANITE, p. 263. H.=55-6 ; G.=3-42 ; monoclinic ; bnh pitch- 

 black, streak gyh, bnh ; B.B. fuses easily ; most varieties gelat. 

 with H CI. 



WOLFRAMITE, p, 183. H.=5-5'5; G.=7-l-7'6; monoclinic; gyh 

 black or bnh black ; B.B. fuses easily, and reacts for iron, manga- 

 nese, and tungsten. 



B. INFUSIBLE OR NEARLY SO. 



a. REACTION FOR IRON ; ANHYDROUS; H.=5-6'5. 



MAGNETITE, p. 178. G. =4*9-5 2 ; isometric ; iron-black ; streak 



black ; strongly magnetic. 

 MENACCANITE, p. 178. G. =4*5-5 ; rhombohedral ; iron-black ; 



streak submetallic, black to bnh red ; very slightly magnetic. 

 HEMATITE, p. 176. G.=4'5-5'3; rhombohedral; gyh iron-black, 



in very thin splinters or scales blood-red by transmitted light ; 



streak red ; sometimes slightly magnetic. 

 MARTITE, p. 177. Same as hematite, but isometric. 

 TANTALITE, p. 184. G.=7-8; trimetric; iron-black, streak rdh 



brown to black. 



