FUSIBILITY AND 1IAI!I>\ESS ABOVE 5 lisl 



ft. The eneentr:i1e<l H( '1 solution yields a precipitate 

 with HjSO4 (calcium). 



Gehlenite, (Ca.Mg.Fe \ : ^ < ),; Grayish green, brown ; 

 H. 5.5-6; G. 2.98; F. 5; II. 



y. Yields a test for the rare earths. 



GADOLINITE, FeB 2 Y 2 Si 2 O, ; Black, greenish black, 

 brown ; H. 6.5-7 ; G. 4.25 ; V. 



Thorite, ThSiO 4 ; Orange-yellow, brown, black; Resi- 

 nous; Cl. prismatic ; H. 5; G. 4.90; II. 

 c. Insoluble in HC1. 

 -a. Yields a fine blue with cobalt solution. 



CORUNDUM, A1 2 O 3 ; All colors; Cl. rhombohedral ; 

 H. 9; G. 4.03; III; p. 341. 



CYANITE, Al(A10)SiO 4 ; Blue, gray, white, green; Cl. 

 pinacoidal; H. 5-7; G. 3.62; VI; p. 461. 



ANDALUSITE, Al(AlO)SiO 4 ; Flesh-red, reddish brown, 

 olive; Cl. prismatic; H. 7.5; G. 3.18; IV; p. 459. 



SILLIMANITE, Al(A10)SiO 4 ; Brown, gray, greenish 

 gray; Cl. pinacoidal; H. 6-7; G. 3.23; IV; p. 461. 



Dumortierite, Al 2 (AlO) 6 (SiO 4 )3; Deep blue; Cl. pina- 

 eoidal; H. 7; G. 3.26; IV. 



TOPAZ, Al(Al(O.F 2 ))SiO 4 ; White, yellow, pink, bluish, 

 greenish ; Cl. basal ; H. 8 ; G. 3.53 ; IV ; p. 458. 



Kornerupine, Mg(AlO) 2 SiO 4 ; White, yellowish brown; 

 Cl. prismatic ; H. 6.5 ; G. 3.27 ; IV. 



CHRYSOBERYL, BeAl 2 O 4 ; Yellowish to emerald- 

 green ; Cl. prismatic ; H. 8.5 ; G. 3.67 ; IV ; p. 377. 



y. Do not yield a fine blue with cobalt solution, some 

 however may give a dull blue. 



*. Fused with \\ parts of soda yields a bead remain- 

 ing clear when cold. 



QUARTZ, SiO 2 ; All colors; H. 7; G. 2.65; III; p. 352. 



TRIDYMITE, SiO 2 ; White; H. 7; G. 2.30; III; p. 

 361. 



CHALCEDONY, SiO 2 ; Various colors; Waxlike; H. 

 7 ; G. 2.62 ; Massive ; p. 360. 



**. Do not yield a clear bead. 



Shows magnesium c, p. 567. 



ENSTATITE, (Mg.Fe)SiO 3 ; Gray, brown, green; 

 Pearly, bronzelike; Cl. prismatic; H. 5.5-6.5; G. 

 3.20; IV; p. 421. 



