634 MINERALOGY 



Pseudobrookite. Fe 4 (Ti0 4 )3 ; Brownish black ; Str. 



Reddish brown ; H. 6 ; G. 4.94 ; IV. 

 When fused with soda on coal yields an antimony coat. 

 Derbylite, 5 FeTi0 3 .FeSb 2 O 6 ; Pitch-black ; Str. Brown ; 



H. 5; G. 4.5; IV. 



c. The borax bead shows iron only. 



MAGNETITE, Fe 3 O 4 ; Iron-black ; Str. Black ; H. 6 ; 



G. 5.18; I; p. 373. 

 HEMATITE, Fe 2 O 3 ; Steel-gray to iron-black; Str. 



Indian-red; H. 5.5-6.5 ; G. 5.20; III; p. 343. 

 Magnesoferrite, MgO, Fe 2 O 3 ; Iron-black; Str. Black; 



H. 6-6.5; G. 4.6; I; p. 371. 



d. The borax bead is yellow after oxidation with niter, and 



shows chromium ; 6, p. 569. 

 CHROMITE, FeO, Cr 2 O 3 , Iron-black; Str. Brown; H. 



5.5; G. 4.2; I; p. 376. 

 X. Minerals which are not included in the preceding divisions. 



A. Compare chromite, wolframite, and molybdenite in preceding 



sections. 

 GRAPHITE, C; Iron-black; Str. Black; H. 1-1.5; G. 



2.20 ; Cl. Basal ; III ; p. 284. 

 URANINITE, UO 2 , U0 3 ; Black ; Brownish black ; 



H. 5.5; G. 9.35; I; p. 525. 



B. The HCl solution reduced with tin shows titanium; 6, p. 570. 



RUTILE, Ti0 2 ; Brownish black; Str. Yellowish 

 brown ; H. 6-6.5 ; G. 4.22 ; II ; p. 349. 



Brookite, TiO 2 ; Brown to black ; Str. yellowish ; H. 6 ; 

 G. 3.95; IV; p. 351. 



Perovskite, CaTiO 3 ; Brown to black; Str. Grayish; 

 H. 5.5 ; G. 3.95 ; I ; p. 347. 



C. The HCl solution reduced with zinc shows columbium; a, p. 570. 



COLUMBITE, (Fe.Mn)(Cb.Ta) 2 O 6 ; Black; Str. Dark 

 red to black ; H. 6 ; G. 5.68 ; IV ; p. 505. 



Fergusonite, (Y.Er.Ce)(Cb.Ta)0 4 ; Brownish black; 

 Str. Dark brown ; 5.5-6 ; G. 5.80 ; IV ; p. 506. 



Samarskite, (Fe.Ca.UO 2 ) 3 (Y. Er. Ce) 2 (Cb.Ta) 6 2 i ; Vel- 

 vet-black ; Str. Reddish brown ; H. 5-6 ; G. 5.70 ; IV. 



Mossite, Fe(Cb.Ta) 2 O 6 ; Black; Str. Black; H. 6; 

 G. 6.45; IV. 



JEschynite, 4(Ce.La.Er) 5 (Ti.Th)Cb 4 26 ; Black; Str. 

 Gray ; H. 5-6 ; G. 4.93 ; IV. 



